diff --git a/src/components/structures/MessagePanel.js b/src/components/structures/MessagePanel.js
index 9034123e52..b1f88a6221 100644
--- a/src/components/structures/MessagePanel.js
+++ b/src/components/structures/MessagePanel.js
@@ -387,7 +387,7 @@ module.exports = React.createClass({
 
                 ret.push(<MemberEventListSummary key={key}
                     events={summarisedEvents}
-                    onToggle={this._onWidgetLoad} // Update scroll state
+                    onToggle={this._onHeightChanged} // Update scroll state
                     startExpanded={highlightInMels}
                 >
                         { eventTiles }
@@ -517,7 +517,7 @@ module.exports = React.createClass({
                         data-scroll-tokens={scrollToken}>
                     <EventTile mxEvent={mxEv} continuation={continuation}
                         isRedacted={mxEv.isRedacted()}
-                        onWidgetLoad={this._onWidgetLoad}
+                        onHeightChanged={this._onHeightChanged}
                         readReceipts={readReceipts}
                         readReceiptMap={this._readReceiptMap}
                         showUrlPreview={this.props.showUrlPreview}
@@ -625,7 +625,7 @@ module.exports = React.createClass({
 
     // once dynamic content in the events load, make the scrollPanel check the
     // scroll offsets.
-    _onWidgetLoad: function() {
+    _onHeightChanged: function() {
         const scrollPanel = this.refs.scrollPanel;
         if (scrollPanel) {
             scrollPanel.forceUpdate();
diff --git a/src/components/structures/RoomView.js b/src/components/structures/RoomView.js
index 8d55715dbf..2a1c7fe79e 100644
--- a/src/components/structures/RoomView.js
+++ b/src/components/structures/RoomView.js
@@ -1186,7 +1186,7 @@ module.exports = React.createClass({
 
         // once dynamic content in the search results load, make the scrollPanel check
         // the scroll offsets.
-        const onWidgetLoad = () => {
+        const onHeightChanged = () => {
             const scrollPanel = this.refs.searchResultsPanel;
             if (scrollPanel) {
                 scrollPanel.checkScroll();
@@ -1231,7 +1231,7 @@ module.exports = React.createClass({
                      searchHighlights={this.state.searchHighlights}
                      resultLink={resultLink}
                      permalinkCreator={this.state.permalinkCreator}
-                     onWidgetLoad={onWidgetLoad} />);
+                     onHeightChanged={onHeightChanged} />);
         }
         return ret;
     },
diff --git a/src/components/structures/ScrollPanel.js b/src/components/structures/ScrollPanel.js
index 41ee602c68..ee4045c91e 100644
--- a/src/components/structures/ScrollPanel.js
+++ b/src/components/structures/ScrollPanel.js
@@ -79,26 +79,6 @@ if (DEBUG_SCROLL) {
  * offset as normal.
  */
 
-
-function createTimelineResizeDetector(scrollNode, itemlist, callback) {
-    if (typeof ResizeObserver !== "undefined") {
-        const ro = new ResizeObserver(callback);
-        ro.observe(itemlist);
-        return ro;
-    } else if (typeof IntersectionObserver !== "undefined") {
-        const threshold = [];
-        for (let i = 0; i <= 1000; ++i) {
-            threshold.push(i / 1000);
-        }
-        const io = new IntersectionObserver(
-            callback,
-            {root: scrollNode, threshold},
-        );
-        io.observe(itemlist);
-        return io;
-    }
-}
-
 module.exports = React.createClass({
     displayName: 'ScrollPanel',
 
@@ -181,12 +161,6 @@ module.exports = React.createClass({
 
     componentDidMount: function() {
         this.checkScroll();
-
-        this._timelineSizeObserver = createTimelineResizeDetector(
-            this._getScrollNode(),
-            this.refs.itemlist,
-            () => { this._restoreSavedScrollState(); },
-        );
     },
 
     componentDidUpdate: function() {
@@ -204,10 +178,6 @@ module.exports = React.createClass({
         //
         // (We could use isMounted(), but facebook have deprecated that.)
         this.unmounted = true;
-        if (this._timelineSizeObserver) {
-            this._timelineSizeObserver.disconnect();
-            this._timelineSizeObserver = null;
-        }
     },
 
     onScroll: function(ev) {
@@ -601,16 +571,17 @@ module.exports = React.createClass({
         }
 
         const scrollNode = this._getScrollNode();
-        const scrollBottom = scrollNode.scrollTop + scrollNode.clientHeight;
-
+        const scrollTop = scrollNode.scrollTop;
+        const viewportBottom = scrollTop + scrollNode.clientHeight;
         const nodeBottom = node.offsetTop + node.clientHeight;
-        const scrollDelta = nodeBottom + pixelOffset - scrollBottom;
+        const intendedViewportBottom = nodeBottom + pixelOffset;
+        const scrollDelta = intendedViewportBottom - viewportBottom;
 
         debuglog("ScrollPanel: scrolling to token '" + scrollToken + "'+" +
                  pixelOffset + " (delta: "+scrollDelta+")");
 
-        if (scrollDelta != 0) {
-            this._setScrollTop(scrollNode.scrollTop + scrollDelta);
+        if (scrollDelta !== 0) {
+            this._setScrollTop(scrollTop + scrollDelta);
         }
     },
 
@@ -622,7 +593,7 @@ module.exports = React.createClass({
         }
 
         const scrollNode = this._getScrollNode();
-        const scrollBottom = scrollNode.scrollTop + scrollNode.clientHeight;
+        const viewportBottom = scrollNode.scrollTop + scrollNode.clientHeight;
 
         const itemlist = this.refs.itemlist;
         const messages = itemlist.children;
@@ -636,7 +607,7 @@ module.exports = React.createClass({
             node = messages[i];
             // break at the first message (coming from the bottom)
             // that has it's offsetTop above the bottom of the viewport.
-            if (node.offsetTop < scrollBottom) {
+            if (node.offsetTop < viewportBottom) {
                 // Use this node as the scrollToken
                 break;
             }
@@ -652,7 +623,7 @@ module.exports = React.createClass({
         this.scrollState = {
             stuckAtBottom: false,
             trackedScrollToken: node.dataset.scrollTokens.split(',')[0],
-            pixelOffset: scrollBottom - nodeBottom,
+            pixelOffset: viewportBottom - nodeBottom,
         };
     },
 
diff --git a/src/components/views/elements/ReplyThread.js b/src/components/views/elements/ReplyThread.js
index 19b28d37a3..f3cd6e144d 100644
--- a/src/components/views/elements/ReplyThread.js
+++ b/src/components/views/elements/ReplyThread.js
@@ -31,7 +31,7 @@ export default class ReplyThread extends React.Component {
         // the latest event in this chain of replies
         parentEv: PropTypes.instanceOf(MatrixEvent),
         // called when the ReplyThread contents has changed, including EventTiles thereof
-        onWidgetLoad: PropTypes.func.isRequired,
+        onHeightChanged: PropTypes.func.isRequired,
         permalinkCreator: PropTypes.instanceOf(RoomPermalinkCreator).isRequired,
     };
 
@@ -160,11 +160,11 @@ export default class ReplyThread extends React.Component {
         };
     }
 
-    static makeThread(parentEv, onWidgetLoad, permalinkCreator, ref) {
+    static makeThread(parentEv, onHeightChanged, permalinkCreator, ref) {
         if (!ReplyThread.getParentEventId(parentEv)) {
             return <div />;
         }
-        return <ReplyThread parentEv={parentEv} onWidgetLoad={onWidgetLoad}
+        return <ReplyThread parentEv={parentEv} onHeightChanged={onHeightChanged}
             ref={ref} permalinkCreator={permalinkCreator} />;
     }
 
@@ -175,7 +175,7 @@ export default class ReplyThread extends React.Component {
     }
 
     componentDidUpdate() {
-        this.props.onWidgetLoad();
+        this.props.onHeightChanged();
     }
 
     componentWillUnmount() {
@@ -295,7 +295,7 @@ export default class ReplyThread extends React.Component {
                 { dateSep }
                 <EventTile mxEvent={ev}
                            tileShape="reply"
-                           onWidgetLoad={this.props.onWidgetLoad}
+                           onHeightChanged={this.props.onHeightChanged}
                            permalinkCreator={this.props.permalinkCreator}
                            isTwelveHour={SettingsStore.getValue("showTwelveHourTimestamps")} />
             </blockquote>;
diff --git a/src/components/views/messages/MFileBody.js b/src/components/views/messages/MFileBody.js
index 781d340252..7960db0384 100644
--- a/src/components/views/messages/MFileBody.js
+++ b/src/components/views/messages/MFileBody.js
@@ -203,6 +203,17 @@ module.exports = React.createClass({
         };
     },
 
+    propTypes: {
+        /* the MatrixEvent to show */
+        mxEvent: PropTypes.object.isRequired,
+        /* already decrypted blob */
+        decryptedBlob: PropTypes.object,
+        /* called when the download link iframe is shown */
+        onHeightChanged: PropTypes.func,
+        /* the shape of the tile, used */
+        tileShape: PropTypes.string,
+    },
+
     contextTypes: {
         appConfig: PropTypes.object,
     },
@@ -248,6 +259,12 @@ module.exports = React.createClass({
         this.tint();
     },
 
+    componentDidUpdate: function(prevProps, prevState) {
+        if (this.props.onHeightChanged && !prevState.decryptedBlob && this.state.decryptedBlob) {
+            this.props.onHeightChanged();
+        }
+    },
+
     componentWillUnmount: function() {
         // Remove this from the list of mounted components
         delete mounts[this.id];
diff --git a/src/components/views/messages/MImageBody.js b/src/components/views/messages/MImageBody.js
index dd1165cf58..882d315d72 100644
--- a/src/components/views/messages/MImageBody.js
+++ b/src/components/views/messages/MImageBody.js
@@ -34,7 +34,7 @@ export default class MImageBody extends React.Component {
         mxEvent: PropTypes.object.isRequired,
 
         /* called when the image has loaded */
-        onWidgetLoad: PropTypes.func.isRequired,
+        onHeightChanged: PropTypes.func.isRequired,
 
         /* the maximum image height to use */
         maxImageHeight: PropTypes.number,
@@ -144,7 +144,7 @@ export default class MImageBody extends React.Component {
     }
 
     onImageLoad() {
-        this.props.onWidgetLoad();
+        this.props.onHeightChanged();
 
         let loadedImageDimensions;
 
diff --git a/src/components/views/messages/MVideoBody.js b/src/components/views/messages/MVideoBody.js
index f1199263e7..e864b983d3 100644
--- a/src/components/views/messages/MVideoBody.js
+++ b/src/components/views/messages/MVideoBody.js
@@ -33,7 +33,7 @@ module.exports = React.createClass({
         mxEvent: PropTypes.object.isRequired,
 
         /* called when the video has loaded */
-        onWidgetLoad: PropTypes.func.isRequired,
+        onHeightChanged: PropTypes.func.isRequired,
     },
 
     getInitialState: function() {
@@ -108,7 +108,7 @@ module.exports = React.createClass({
                         decryptedThumbnailUrl: thumbnailUrl,
                         decryptedBlob: decryptedBlob,
                     });
-                    this.props.onWidgetLoad();
+                    this.props.onHeightChanged();
                 });
             }).catch((err) => {
                 console.warn("Unable to decrypt attachment: ", err);
diff --git a/src/components/views/messages/MessageEvent.js b/src/components/views/messages/MessageEvent.js
index fd51e6074b..010b1d8751 100644
--- a/src/components/views/messages/MessageEvent.js
+++ b/src/components/views/messages/MessageEvent.js
@@ -37,7 +37,7 @@ module.exports = React.createClass({
         showUrlPreview: PropTypes.bool,
 
         /* callback called when dynamic content in events are loaded */
-        onWidgetLoad: PropTypes.func,
+        onHeightChanged: PropTypes.func,
 
         /* the shape of the tile, used */
         tileShape: PropTypes.string,
@@ -89,6 +89,6 @@ module.exports = React.createClass({
             showUrlPreview={this.props.showUrlPreview}
             tileShape={this.props.tileShape}
             maxImageHeight={this.props.maxImageHeight}
-            onWidgetLoad={this.props.onWidgetLoad} />;
+            onHeightChanged={this.props.onHeightChanged} />;
     },
 });
diff --git a/src/components/views/messages/TextualBody.js b/src/components/views/messages/TextualBody.js
index ec8c18cd7e..1b6c9418a9 100644
--- a/src/components/views/messages/TextualBody.js
+++ b/src/components/views/messages/TextualBody.js
@@ -52,7 +52,7 @@ module.exports = React.createClass({
         showUrlPreview: PropTypes.bool,
 
         /* callback for when our widget has loaded */
-        onWidgetLoad: PropTypes.func,
+        onHeightChanged: PropTypes.func,
 
         /* the shape of the tile, used */
         tileShape: PropTypes.string,
@@ -451,7 +451,7 @@ module.exports = React.createClass({
                             link={link}
                             mxEvent={this.props.mxEvent}
                             onCancelClick={this.onCancelClick}
-                            onWidgetLoad={this.props.onWidgetLoad} />;
+                            onHeightChanged={this.props.onHeightChanged} />;
             });
         }
 
diff --git a/src/components/views/rooms/EventTile.js b/src/components/views/rooms/EventTile.js
index 804789f306..d7c9f1e443 100644
--- a/src/components/views/rooms/EventTile.js
+++ b/src/components/views/rooms/EventTile.js
@@ -129,7 +129,7 @@ module.exports = withMatrixClient(React.createClass({
         isSelectedEvent: PropTypes.bool,
 
         /* callback called when dynamic content in events are loaded */
-        onWidgetLoad: PropTypes.func,
+        onHeightChanged: PropTypes.func,
 
         /* a list of read-receipts we should show. Each object has a 'roomMember' and 'ts'. */
         readReceipts: PropTypes.arrayOf(React.PropTypes.object),
@@ -165,8 +165,8 @@ module.exports = withMatrixClient(React.createClass({
 
     getDefaultProps: function() {
         return {
-            // no-op function because onWidgetLoad is optional yet some sub-components assume its existence
-            onWidgetLoad: function() {},
+            // no-op function because onHeightChanged is optional yet some sub-components assume its existence
+            onHeightChanged: function() {},
         };
     },
 
@@ -223,7 +223,7 @@ module.exports = withMatrixClient(React.createClass({
      */
     _onDecrypted: function() {
         // we need to re-verify the sending device.
-        // (we call onWidgetLoad in _verifyEvent to handle the case where decryption
+        // (we call onHeightChanged in _verifyEvent to handle the case where decryption
         // has caused a change in size of the event tile)
         this._verifyEvent(this.props.mxEvent);
         this.forceUpdate();
@@ -245,7 +245,7 @@ module.exports = withMatrixClient(React.createClass({
             verified: verified,
         }, () => {
             // Decryption may have caused a change in size
-            this.props.onWidgetLoad();
+            this.props.onHeightChanged();
         });
     },
 
@@ -667,7 +667,7 @@ module.exports = withMatrixClient(React.createClass({
                                            highlights={this.props.highlights}
                                            highlightLink={this.props.highlightLink}
                                            showUrlPreview={this.props.showUrlPreview}
-                                           onWidgetLoad={this.props.onWidgetLoad} />
+                                           onHeightChanged={this.props.onHeightChanged} />
                         </div>
                     </div>
                 );
@@ -682,7 +682,7 @@ module.exports = withMatrixClient(React.createClass({
                                            highlightLink={this.props.highlightLink}
                                            showUrlPreview={this.props.showUrlPreview}
                                            tileShape={this.props.tileShape}
-                                           onWidgetLoad={this.props.onWidgetLoad} />
+                                           onHeightChanged={this.props.onHeightChanged} />
                         </div>
                         <a
                             className="mx_EventTile_senderDetailsLink"
@@ -704,7 +704,7 @@ module.exports = withMatrixClient(React.createClass({
                 if (this.props.tileShape === 'reply_preview') {
                     thread = ReplyThread.makeThread(
                         this.props.mxEvent,
-                        this.props.onWidgetLoad,
+                        this.props.onHeightChanged,
                         this.props.permalinkCreator,
                         'replyThread',
                     );
@@ -723,7 +723,7 @@ module.exports = withMatrixClient(React.createClass({
                                            mxEvent={this.props.mxEvent}
                                            highlights={this.props.highlights}
                                            highlightLink={this.props.highlightLink}
-                                           onWidgetLoad={this.props.onWidgetLoad}
+                                           onHeightChanged={this.props.onHeightChanged}
                                            showUrlPreview={false} />
                         </div>
                     </div>
@@ -732,7 +732,7 @@ module.exports = withMatrixClient(React.createClass({
             default: {
                 const thread = ReplyThread.makeThread(
                     this.props.mxEvent,
-                    this.props.onWidgetLoad,
+                    this.props.onHeightChanged,
                     this.props.permalinkCreator,
                     'replyThread',
                 );
@@ -753,7 +753,7 @@ module.exports = withMatrixClient(React.createClass({
                                            highlights={this.props.highlights}
                                            highlightLink={this.props.highlightLink}
                                            showUrlPreview={this.props.showUrlPreview}
-                                           onWidgetLoad={this.props.onWidgetLoad} />
+                                           onHeightChanged={this.props.onHeightChanged} />
                             { keyRequestInfo }
                             { editButton }
                         </div>
diff --git a/src/components/views/rooms/LinkPreviewWidget.js b/src/components/views/rooms/LinkPreviewWidget.js
index 78796a8f14..5f32a6a613 100644
--- a/src/components/views/rooms/LinkPreviewWidget.js
+++ b/src/components/views/rooms/LinkPreviewWidget.js
@@ -32,7 +32,7 @@ module.exports = React.createClass({
         link: PropTypes.string.isRequired, // the URL being previewed
         mxEvent: PropTypes.object.isRequired, // the Event associated with the preview
         onCancelClick: PropTypes.func, // called when the preview's cancel ('hide') button is clicked
-        onWidgetLoad: PropTypes.func, // called when the preview's contents has loaded
+        onHeightChanged: PropTypes.func, // called when the preview's contents has loaded
     },
 
     getInitialState: function() {
@@ -49,7 +49,7 @@ module.exports = React.createClass({
             }
             this.setState(
                 { preview: res },
-                this.props.onWidgetLoad,
+                this.props.onHeightChanged,
             );
         }, (error)=>{
             console.error("Failed to get preview for " + this.props.link + " " + error);
diff --git a/src/components/views/rooms/PinnedEventTile.js b/src/components/views/rooms/PinnedEventTile.js
index 3253340a76..8b2b217e19 100644
--- a/src/components/views/rooms/PinnedEventTile.js
+++ b/src/components/views/rooms/PinnedEventTile.js
@@ -92,7 +92,7 @@ module.exports = React.createClass({
                 </span>
                 <div className="mx_PinnedEventTile_message">
                     <MessageEvent mxEvent={this.props.mxEvent} className="mx_PinnedEventTile_body" maxImageHeight={150}
-                                  onWidgetLoad={() => {}} // we need to give this, apparently
+                                  onHeightChanged={() => {}} // we need to give this, apparently
                     />
                 </div>
             </div>
diff --git a/src/components/views/rooms/SearchResultTile.js b/src/components/views/rooms/SearchResultTile.js
index eff3fdc89d..e396ea7011 100644
--- a/src/components/views/rooms/SearchResultTile.js
+++ b/src/components/views/rooms/SearchResultTile.js
@@ -33,7 +33,7 @@ module.exports = React.createClass({
         // href for the highlights in this result
         resultLink: PropTypes.string,
 
-        onWidgetLoad: PropTypes.func,
+        onHeightChanged: PropTypes.func,
     },
 
     render: function() {
@@ -58,7 +58,7 @@ module.exports = React.createClass({
                 ret.push(<EventTile key={eventId+"+"+j} mxEvent={ev} contextual={contextual} highlights={highlights}
                           permalinkCreator={this.props.permalinkCreator}
                           highlightLink={this.props.resultLink}
-                          onWidgetLoad={this.props.onWidgetLoad} />);
+                          onHeightChanged={this.props.onHeightChanged} />);
             }
         }
         return (