I have a biggish project with a large canvas control which is contained in a page panel, since upgrading to 2016 r2 erasebackground (and/or doublebuffer) only erases the left two thirds of the canvas. There are no controls that overlap the whole of the un-erased area… I can work around the problem so I’m not desperately seeking a solution but I’m curious if anyone else has come across anything similar?
Which OS?
With what version did it last work properly?
It would greatly help if you filed a bug report with a project demonstrating the problem attached. So people can see if they can reproduce the issue.
From the doublebuffer thing, should I guess what you experience is on Windows ? Windows 10 or previous ?
It’s on OS X el cap and built fine up to 2016 r1.1. I just experimentally turned on double buffer when I was trying to solve the problem. Turning off erase background and filling the empty space with a rectangle works round the problem. I’ll try and reproduce it in a small project.
I was vaguely hoping someone would go … “Yeah that always happens you just need to …” 
Building a small test project with same controls in r1.1 then opening in r2 … works perfectly … obviously 
AFAIK Double buffer being built in the hardware, setting it on adds nothing on Mac. It is most useful on Windows where it drastically reduces flicker.