Fix page up/page down scrolling only half a page

Signed-off-by: Aaron Raimist <aaron@raim.ist>

src/components/structures/ScrollPanel.js

@@ -525,7 +525,7 @@ export default class ScrollPanel extends React.Component {
      */
     scrollRelative = mult => {
         const scrollNode = this._getScrollNode();
-        const delta = mult * scrollNode.clientHeight * 0.5;
+        const delta = mult * scrollNode.clientHeight;
         scrollNode.scrollBy(0, delta);
         this._saveScrollState();
     };