If monitors are configured to different DPIs, StartIsBack opened from the DF taskbar does not honour the DPI setting and assumed 100%. StartIsBack opened from the Windows taskbar on the same monitor does not suffer from this issue.

If you are using a theme that includes shadows around the border (Installing Glass8 will make this happen) and have a maximised window that is bordering the taskbar on an adjacent monitor, that taskbar will glitch out when the maximised window is scrolled, causing part of the taskbar to disappear until you click on it again.

The icons seem to be generated by scaling, rather than using the alternate images in a .ico file. This means they look lower quality and blurry compared to the Windows taskbar

Here you go...

I've also noticed that the font rendering DF uses doesn't quite match the one used by the rest of the OS. It's hard to put my finger on exactly what the difference is, but it's there, the DF font's look a bit rougher and more pixellated compared to the Windows ones.

Easiest place to spot it is on the right-click taskbar menu for a pinned icon, and compare to the Windows version.

This page seems to be a good one for reproducing the fault:

https://www.displayfusion.com/AdvancedSettings/?Version=8.1.1.0

kinda ironic in a way

I've noticed that force-enabling e10s in Firefox seems to cure the glitch, odd but as long as none of my (many) addons are broken by it, I'll run with it!

Ok my bad. The glitch seems to be down to either a theme or a driver issue. I eventually got it to occur on another app's window, nothing to do with DF, it must have just gotten brought about when I added 2 monitors to this laptop.

The other two are still a problem though