Please imagine the following situation:
In my IDE in the main window I have two sub-windows opened - the project window on the left, the source window on the right. The output window is minimized at the bottom border of the main window.

If I maximize the output window using its icon on the border, i can minimize it back clicking anywhere inside of any other opened window.

But if the output window is activated automatically as a consequence of another action (e.g. F9 - Compile File) it cannot be minimized by clicking the window that was active when the action was started. Clicking the other window works. In other words, if I start the compiler (F9) being in the source window, the output window pop-ups but cannot be minimized back clicking the source window. Similarly, if I select a source file in the project window and press F9, I cannot minimize the output window clicking the project window. I must always click the other window that was inactive as the action was started.