Ribbonwindow does not show right when made visible

I have a strange problem.

Our application X loads a second program Y at the background that stays invisibile until it is needed.
(This program has a actipro ribbonbar)

Sometimes when i click on a button in X to show Y, the application is shown, but the layout is messed up. Looks like some auto size container do not resize or something. When i change the windowsize and let it go, everything is back to normal again??

I have the same when i go back from Y to X (when Y is shown, X is made invisible). The screen with calender and other content is frozen until i resize the window.

I did not have this problem with 2012.2. It occures with 2013.1.
Is there anybody who has seen the same problem????