Other RED viewports not rendered after maximizing one, then resizing

[GooberRF]

Issue is displayed in screenshot. To reproduce:

1. Open RED
2. Hover over any viewport (do not use the bottom right viewport or the editor will crash, as detailed in Dash RED crashes when maximizing viewport in bottom right slot #117 )
3. Hit F4 to maximize the active viewport
4. Manually drag the viewport border so that viewport is no longer maximized
5. Other viewports will not render (in my case they display as full white)

You can go back to normal behaviour after this by hitting F5 to restore all viewports to their original size. Notably this issue only occurs when a viewport is maximized via F4, not if a viewport is maximized by manually dragging the viewport border.

Admittedly this is a low priority issue, and is completely avoidable if you know about it. Still though, it can be very confusing especially the first time you encounter it.