I have a fairly simple application I'm currently roughing out.

I have a screen with a RadGrid.  This is bound by a query to a Linq data source.  (Not the control, a direct call to the context using a Linq query.)   I've defined a FormTemplate popup with a bound RadComboBox on it.  The RadComboBox is bound in the ItemCreatedEvent.

Basically everything is working perfectly except that the combo box will not drop down when I click on it.  If it has the focus I can change the setting by using the arrow keys and when I save, the changes are properly saved.  It just won't drop down. 

(Actually this is only true in IE and FireFox.  When it comes up in Chrome, it displays the correct value but then if I click on it and try to use the arrows, it goes blank.)

I probably should mention that when I replace the RadComboBoxes with ordinary Asp.Net dropdown lists, everything works fine.

Hello Boris,

In order to identify the reason for the experienced problem my suggestion is to open a support ticket and provide a runnable sample which we could test locally.

Kind regards,
Dimitar Terziev
the Telerik team

Actually I've solved this part of the problem.  I didn't set the height property. 

Now my problem is that the choice list is displaying horizontally not vertically.

Hi Boris,

As mentioned in my previous post, please open a support ticket and provide a runnable sample so we could help you troubleshoot the experienced problem.

All the best,
Dimitar Terziev
the Telerik team

Apologies for taking so long to respond on this one.

The real problem was that I had forgotten some unrelated styling CSS in the site's master page that was accidentally formatting the RadCombo boxes as well.  (Learning experience!)