Reproduction steps:(Gif attached)
1) Open users attached project.
2) In the toolbar click Test Bug > Open Window with Bug.
3) Stretch window inwards - Notice you can't make it smaller past EditorWindow.minSize;
4) Stretch window outwards.

Expected result: Window does not stretch past EditorWindow.maxSize.
Actual result: You can stretch window outwards as much as you want.

Note 1: This works fine on Mac.
Note 2: Clicking and dragging window that is stretched past EditorWindow.maxSize clamps its size back to EditorWindow.maxSize.

Reproduced with: 5.3.2p1 5.4.0b3 5.2.4f1 5.1.4f1