Lets say I have an application window which has a size of 1727x921. Then I have 4 ToolWindows which are next to each other horizontically. Now two of these 4 toolwindows have a fixed width. The first one of 1000 and the other of 300. If I start the application, it works as expected.
However now the user will resize the application window to make it smaller, from 1727 width to 1711. What happens is that all 4 toolwindows will have the same width, minimum size is ignored. Although 1000 + 300 < 1711. There should be enough width left.
I've modified the ContainerSizeRestriction example and created a GIF demonstrating the issue:
The problem besides the visual glitch is also that, if these 4 toolwindows all have the same width, you can no longer use the resize bar between them to change the width via dragging the mouse cursor. They react like all have a fixed size: