I can try opening the bug report, but please note that I am not experiencing the issue, so I can’t be of much help in debugging it either. That’s why I was suggesting to @PanoMeister to actually report the bug, because he then can provide further info to the GTK devs so that they can pinpoint the problem and hopefully implement a solution.
BTW, one more comment:
Sure, I understand. But you should also understand that RT (like many free/open source projects) is a community effort, meaning that it is done by the community and for the community, which consists of both developers and users. Developers contribute by writing code, users contribute by providing feedback, reporting bugs, interacting in the forum, etc. People who have no interest in helping can still get to use the software for free, but they won’t get much attention if they complain… or, at least, they won’t get much attention from me 
– (I obviously cannot speak for the other developers).
So, the new bottom line: thanks for your help so far, it would be great if you could still help us by reporting the bug to the GTK devs (using the link provided by @Morgan_Hardwood) so that everybody can benefit from an improved GTK and RT. If not, no problem, just send me your credit card number and I will give you back your money 