Mail only visible in Fullscreen

Mail only visible in Fullscreen

Running Opera 10.10 Build 1893 on XP sp3, ATI graphics chipset on Gigabyte board. 2Gig ram
This post refers to Opera's eMail Client M2

This is an odd one.
Happened out of the blue in mid session (had just been to Open Office site to get info for someone else)
Clicked on Mail icon in side panel, the eMail tab opened as usual but the screen remained on the Open Office site. The mail tab was highlighted so I clicked on the other tab, no change. With multiple tabs open I can switch between web pages but when I try to switch to the mail tab all I get is grey screen. However, if I press f11 it will go to fullscreen and the mail window is there. This also happens with Contacts (grey screen but works in fullscreen)
[Edit]
I have since found that if the "reply" function is activated from the fullscreen mail window the reply window functions as normal. ie. can switch back and forth between tabs.
I reinstalled 10.1 a few weeks back, after the appalling 10.51 auto update, and have just run a repair install.
Any help would be appreciated and if I find a solution I will post it here.
Cheers,
Steve.

I will post a screenshot of the mail window in normal screenClipboard01.jpg

The mail tab is either minimized or in "restored" state outside of the opera window. If you right-click the tab, there's the option to maximize it (or all tabs) - do that