Hello Telerik team,

We have a solution that uses lots of dockingpanels aswell as other containers. Inside some of the controls we have radComboBoxes. They all have a peculiar behavior when the app is started. If I click anywhere on the page and then click a drop down arrow -> all is ok.
If I start by clicking on any combo boxes' drop down arrow, the list appears for half a second and then disappears. After this all works normally again. If I instead click right on the comboBox and have OpenDropDownOnFocus= true, then the ComboBox works as expected. So only when clicking on the 'arrow'.
I quit, run the solution, and I can reproduce the behavior every time. 
I tried with a plain radComboBox with no binding and no flags set, just two comboBoxItems hard coded - same behavior.
We tried with a fresh project, just one empty layoutroot and a radcombobox, works like a charm. 
So, somewhere along the line with all our DockingPanels, Grids, StackPanels etc something is messing with the radComboBox. I tried to set the focus() on various objects at initialization, but this has no effect.

Thank you for any directions you could point me to.

Hello Rainer,

Unfortunately, without a sample application in which we can observe the issue, there is not much that can be done. If you manage to reproduce it in a simplified project and send it back to us, we will be able to debug it locally and track down the source of the problem.

Looking forward to your reply.

Kind regards,
Konstantina
the Telerik team