Bug 334786

Description Andreas Ehret 2011-01-19 09:15:14 EST

Build Identifier: 20100617-1415

If I create a TableCombo with a number of items less or equals the visibleItemCount, the height of the drop down part of the combo is not correct, but too small, which leads to a unneccessary scroll bar. In case of having only a single item, its even not possible to select the item at all using the mouse, as the height of the drop down area seems to be zero. 

I found the problem in the dropDown(boolean drop) method where the itemCount is computed. For some reason the itemCount is decremented by 1 in cases where the item count is smaller than the visibleItemCount. If I remove the -1 in the line

itemCount = (itemCount == 0) ? visibleItemCount : Math.min(visibleItemCount, itemCount) - 1;

that seems to solve this problem. There is, however, still an empty row at the end, which appears to me the space for the horizontal scroll bar. In my case no scroll bar is required as the combo item is smaller that the combo itself, so code like the following solves this issue:

if (itemCount <= visibleItemCount) {
   if (table.getHorizontalBar() != null && !table.getHorizontalBar().isVisible()) {
      itemHeight -= table.getHorizontalBar().getSize().y;
   }
}

Reproducible: Always

Steps to Reproduce:
1. create a TableCombo snippet (don't modify the visibleItemCount which is 7 by default) 
2. fill the combo with a single item
3. run the snippet and try to select the item using the mouse