Bug 496261

Description Stephan Krall 2016-06-16 11:14:58 EDT

Created attachment 262497 [details]
Snippet outlining the bug

Content of the Grid Widget gets truncated by the vertical 
Scrollbar if certain preconditions are fulfilled and Scrollbar has no "show on hover" (i.e. show always when visible property is set) behaviour due
to a modified CSS.

First the tree must not be shallow (deep hierarchy). Second, the total column
width must be slightly smaller than the width of the Grid. Third, the size of the content
of the first column must be larger than its initial bounds. Additionally for the GridTreeViewer viewer, viewer.getGrid().setAutoHeight() must be called.
Finally the height of all items (root and expanded ones) must not exceed the height of 
the clientArea of the Grid. If this preconditions are fulfilled and the elements of 
the Grid are expanded then a vertical Scrollbar is displayed but not
a horizontal one, thus truncating the content of the last column if
its style is set to SWT.RIGHT. Furthermore the status change (Scrollbar hidden -> not hidden) is not communicated to the server. 

This error is due to a bug in the method Grid._getLastPageRowCount (used by _updateScrollHeight) which calculates the height incorrectly using GridItem.getOwnHeight. More specifically the method does not consider the expanded child elements in its calculation. _updateScrollHeight is called
due to a event emitted during the render phase which in turn is trigged by changing the height of the dom element of the corresponding
GridItems due to viewer.getGrid().setAutoHeight(). For further details please see the attached snippet.