[Trisquel 7.0, Inkscape trunk r14924]
Open the attached file and press F2 (switch to the node tool) and Shift+Ctrl+7 (open the path effects dialogue). Click once in the exact middle of the red circle and IMMEDIATELY yank the mouse right. The selected path then fails to render, a white rectangle appearing over it. Upon returning to the select tool (F1), the white rectangle increases in size; zooming in or out restores the original appearance.
This bug does not manifest if any of the following is true at the time of yanking:
(1) the node tool is not being used
(2) the path effects dialogue is not open
(3) Inkscape is using GTK+ 3
(4) the version is 0.91
The report here is one of a series of canvas oddities in the current GTK+ 2 Inkscape trunk, which possibly includes bug #1571192. The Hackfest commits introduced all these bugs, and I suggest reverting those commits until the bugs no longer manifest.
(Also, why are the developers not fixing the critical bugs first?)
Bug and workatounds conformed on Xubuntu 16.04, Inkscape trunk rev. 14942.