Hello Dimitar,
Just tested again with version 3.5 and i see the same behavior. (all current browsers on windows 7/32). So i guess that you and i test differently.
Once the vertical scroll bar appears it is not possible anymore to re-size the window pulling on the right side of the window. Pulling on the left side remains possible.
When the window is small enough to show a vertical scroll bar it’s possible to enlarge the window vertically, by pulling the top of the window, once the scroll bar disappears re-sizing horizontally from the right side of the window is possible again.
Hope this makes it more clear
Thanks, Rob