Looks like we can't reproduce the issue or there's a problem in the test case provided.
Ext GWT Premium Member
combo-box drop-down to be wide enough to show long values
Would like ComboBox to have the ability for the drop-down list to be as wide as the data in the list, even if the displayed column is not very wide. If users resizes column in grid, would like that not to have negative impact to a combo box in the grid.
Screenshot shows cropping of colors "mother of pearl" and "very, very dark red"...
Thanks for the report. I've filed this as a bug and will update here with any changes.
Although we'll register this as a feature to consider in future revisions, we're not interested in incorporating this into the library proper right now. Thanks for your suggestion.