OpenMW-CS menu system crashing on XFCE

OpenMW-CS has been totally unusable in Manjaro XFCE lately. When any table is opened a few times in a row, the toolbars start to flicker, until they disappear, redraw, until finally the whole windowing system crashes. I wrote about this bug earlier here #5481 (comment 454581908) , but it's not directly related to that issue. It might require a fix in Qt, but it can also be fixed in OpenMW side by creating QStatusBar with a parent. I'll test this once more, and submit a MR soon.

edit: Oh yes, random crashing was a 0.47 blocker. So if this works on all platforms, that's one blocker less.