System Information
Operating system: Windows-10-10.0.17763-SP0 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.92

Blender Version
Broken: version: 2.90.0 Alpha, branch: master, commit date: 2020-06-02 22:21, hash: rB2e52b3206cc6
Worked: (newest version of Blender that worked as expected)

Short description of error
the file view is squashed right down on the 4k monitor every time it's opened from an image editor on a 1080p monitor, resizing doesnt take effect next time opened. Also the amount the file view is squashed down is dependant on whether or not the image editor is full screen or not the first time it's called after initially opening the image editor:

image editor not full screen on second monitor:

Not sure if this is related to the bug that causes blender to need taking out of full screen and then back into full screen after rendering in order for the workspace tabs and menus across the top to become responsive, as this also only happens on dual monitor setups.