Issue: Eto Combobox events don't seem to be recorded inside a TreeGrid

[timcastelijn]

Hi there,

I am using an Eto Combobox inside a TreeGrid to manipulate some data. I use the .SelectedIndexChanged event to record any changes.

The mechanism works for comboboxes where the expanded area is inside the TreeGrid bounds. However, Events on any item that are outside the treegrid bounds are not recorded unexpectedly (see screenshot/video)

Can anyone please help me with that?
I’ve attached my sample code below

Thanks,
Tim

sample code:

sample_dropdown.py (6.0 KB)

[Cole_Howell1 (Cole Howell)]

This is a known problem with ComboBoxCell. I and several others have had multiple issues using it. My own report on it is here:

Unexpected ComboBoxCell Behavior

Working on some UI elements, I noticed that combo box cell is a bit unwieldy and has unexpected behavior. Most pressing is that changes are not committed as expected under certain circumstances. [Screenshot 2025-10-07 092238] internal class EtoBug: Dialog { string[] dropdatastore = new string[] { "Test 1", "Test 2" }; public EtoBug() { Size = new Size(300, 300); var example = new GridView(); example.Columns.Add(new GridColumn { …

There doesn’t seem to be a fix to it currently. In the meantime, I’ve found you can begin editing the combo box, then type the first few letters of the selection you want to make in order to change it. Another workaround is to dynamically change the size of the tree grid view to only contain the items, so there is no empty space to take the focus from the cell to the view.

Because this is a such a prevalent issue, I’ll see if I can dedicate some time to a sufficient workaround and will update my thread if successful.

[timcastelijn]

hi @Cole_Howell1,

thanks for your reply. Changing the size of the TreeGridView to leave no ‘empty’ space, sounds like a good workaround for my case. Looking forward to see your solution.