Inkscape trunk suddenly very slow

To reproduce:
1. Open Inkscape-trunk
2. Draw a circle
3. Try to drag the circle around the canvas

Result: Slow and choppy

To compare:
1. Open Inkscape 0.91
2. Draw a circle
3. Try to drag the circle around the canvas

Result: Smooth and nice, like Inkscape is normally.

This slowdown is everything from dragging to text entry, etc. It seems to have only appeared in the last several days.

System Specs: Ubuntu 16.04, 2.4Ghz Intel i5 processor, 16GB RAM, Gnome 3.18

Several others in the inkscape-devel IRC channel have confirmed this is a problem.

I have reverted to 0.91 in the meanwhile to resume work for the Inkscape UI team at a reasonable pace.

Thanks.

-C

Update: (Circle-dragging working fine for me now, but make a line with arrowhead and try to drag it around, and it becomes slow again)