Webkit: content area disappears when resizing the browser

[Jakub Ś]

To reproduce:

1. Open sharedspaces.html sample
2. First two content areas in first two editors should not be visible. If they are just resize the browser.
3. If they are not visible try doing CRTL+F5 few times (they should show) and resize browser again

Result: There are no content areas in first two editors.

Issue can be reproduced in Webkit from CKEditor 3.6.3 rev [7387]

[Garry Yao]

Fixed with [7528].