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GuillaumeCHAFFAROD-9299 asked GuillaumeCHAFFAROD-9299 commented

WPF window displayed using Show (not ShowDialog) in VSTO project - ComboBox issue

In a VSTO 2010 solution (Excel workbook document-level), when a Window containing a ComboBox is displayed using Show() instead of ShowDialog() the popup list will close as soon as the mouse is released, contrary to expected behavior of remaining open until a selection is made or the control loses focus.

Moreover, if the ComboBox is clicked and released (causing the list to flash on and off) without a selection being made, the window itself (the top bar and minimize/maximize/close buttons) is not clickable.
Other controls in the window body continue to function.

We have a plugins system that allows developpers to extend functions of the main application and they may create WPF windows as well as display them using Show (and not ShowDialog) so we can't use custom hack as it would mean that we ask every third parties developers to do so and it's not acceptable.

Thank you very much for providing us a solution.

Best regards,


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Moreover, I didn't test but believe that the issue can also be fired with context menus

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Tried on Excel 2013 instead of 2010, now the combobox items displays properly but once I select any item not actually selected, the list disapear. I have to stay clicked to be able to select a new item.

I could ask my customer to forget about the 2010 compatibility but if it's also on 2013 it will really be difficult for him to ear that.

Someone tested for me with office 365 and it's working for him...

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