In my experience with this, pressing the mapped key does NOT show the toolbar UNTIL you move the mouse to the vicinity where the tool bar is located, THEN it opens up just fine.
However, prior to the 1.2.7.0 patch, the tool bar would not open about 30% of the time, but after the patch, I flew several different aircraft, in VR, for about 4 hours, and the tool bar opened every time without issue. (Again, after I moved the mouse up to the top of the view.)