Locals & Watchers column size is not adapted when expanding watchers

1. Open project qtdeclarative\examples\quick\demos\samegame\samegame.qmlproject from Qt5's repository.
2. Configure the project to run on Qt 5.4.
3. Set a breakpoint at the first line of function startNewGame(gc, mode, map).
4. Run the project in debugger.
5. In the app click "1 Player".
   The breakpoint is being hit.
6. In "Locals and Expressions" view, right-click "this" and select "Add Expression Evaluator for 'this'" from the context menu.
   An expression evaluator for "this" will be added in the lower part of the "Locals and Expressions" view.
7. Expand "this" in the lower half of "Locals and Expressions" view but not in the upper half.
   You'll see this:
   
8. Expand "this" in the upper half of "Locals and Expressions" view.
   Now "this" will be displayed completely:
   

The "Locals and Expressions" view should display the values of expression evaluators correctly, no matter whether locals are expanded or not.