No Dropdown Menu in Registration Key Box

[Chim]

I just finished performing a clean install of avast 7.0.1426 on my computer.
I removed avast 6.x with the Windows Add / Remove function in Safe Mode. 
Then I ran the avast Uninstall Utility in Safe Mode.
Then I cleaned any remnants with CCleaner, JetClean and Glary Utilities.

When I try to insert the Registration Key by Right Clicking in the appropriate box, the Dropdown Menu doesn't display.
There is a faint vertical line like the Dropdown Menu vaguely wanted to display.
But, it just never quite makes it.

Any ideas?
Or is it going to be one of those Repair avast things?

I installed avast 7.0.1426 also on my sister's computer yesterday.  (Okay, so that is my Dell.)
I didn't get around to checking whether that one is doing the same thing because we didn't have the Registration Key yet by the time I had to leave last night.

[Chim]

I just finished performing the Repair of avast.
Still no dropdown menu.

[NON]

Maybe the same issue with this:
[7.0.1426] Tooltips and Context Menus don't show
http://forum.avast.com/index.php?topic=93118.0

This issue is since v7 early beta.

[DavidR]

I don't know if it is, as so far only tooltips and context menu (right click) options don't show, just the shadow outline of where the data should be. I can't recall this also happening with drop down lists. Unfortunately I can't check this with the enter registration key as I still have 352 days remaining.

Does the line look like the attached image ?

Any other drop down lists you have come across displaying (excuse the pun) the same symptoms, that we might check ?

[Chim]

Thanks for that link to that thread, NON.
YES, David, that is exactly what it looks like.
I hadn't noticed the horizontal shadow at the bottom of it before because it lines up right where the Blue-ish bottom border of that Registration Window is.  But, yeah, the horizontal bottom shadow is also there.

I have attached a Screen Cap of it.

I checked just now and it's still doing the same thing.
I'll poke around this morning and see if any other dropdown menus elsewhere are doing the same thing.
But, it's likely that I'll encounter cases like what's mentioned in that other thread to which NON posted the link.