GnuCash 2.6.21 main view redraw issues

0.4.11-RC-33-gb27a643 gcc dbg + VBEMP + inbuilt Mesa + 800x600 32bpp

Reproduction steps
-install MS Visual C++ 2005 from rapps
-install GnuCash 2.6.21 from rapps
-start the main app
-select file/new and create a spreadsheet (to have something in main view)
-then select file / "page setup" from menubar
-cancel the page-setup dlg

Expected result
The dialog should vanish and the main view behind it gets redrawn, like xpsp3.webm

Observed result
The dialog remains, but can be wiggled away with the mouse
0.4.11-RC-33-gb27a643__GnuCash2_6_21_redraw_issues.webm
0.4.11-RC-33-gb27a643__GnuCash2_6_21_redraw_issues.log