Bug 1550902 - Change max size of Secondary and Editor panes r=davidwalsh

Set a maximum size for panes

Differential Revision: https://phabricator.services.mozilla.com/D30743

--HG--
extra : moz-landing-system : lando

devtools/client/debugger/src/components/App.js

@@ -270,14 +270,12 @@ class App extends Component<Props, State> {
     const { startPanelCollapsed, endPanelCollapsed } = this.props;
     const horizontal = this.isHorizontal();
 
-    const maxSize = horizontal ? "70%" : "95%";
-
     return (
       <SplitBox
         style={{ width: "100vw" }}
         initialSize={prefs.endPanelSize}
         minSize={30}
-        maxSize={maxSize}
+        maxSize="70%"
         splitterSize={1}
         vert={horizontal}
         onResizeEnd={num => {