Summary
When you change the SelectedIndex to anything other than -1 in the designer you can't change it back to -1 so that it begins in an unselected state.
Objo Studio Version
26.5.6
Operating System
Select the operating system(s) affected as tags for this post.
Steps To Reproduce
Add a ComboBox to a TabPanel
Add a couple of items with the Add Row button
Change the SelectedIndex to anything other than -1
Try to change the SelectedIndex back to -1 then click any other control on the form
Click back on the ComboBox and the SelectedIndex is 0
Expected Result
SelectedIndex should be -1
Actual Result
SelectedIndex is 0
Screenshots, Logs, Or Sample Project