Join windows problem - simple trick I don't know of?

For joining two windows in either vertical or horizontal direction, I hover over the window edge and Rclick --> Join Area.
This works if the windows have the same width respective height (regarding to Blender Wicki). Nothing special so far.

But for example, if I have divided a window horizontally into two, but want to now join one of them vertically with an adjacent window, blender seems not to let me. I know that the width of the two has to match, but regardless how much I try to eyeball the corners to match, the window still ‘glues’ to the horizontal neighbor.

Is there some trick / Keyboard combination etc. I missed so far to ‘redirect’ the window join priority?

Cheers for any help

Ensue the window corners align with each other.

Please supply an example

You can’t join one window into two other windows.

Sometimes you´ve got a very small Fame open that you don´t notice. For exampel there might be a timeline frame that is allmost completely collapsed. That combined with the fact that you can flip headers makes it easy not to notice.

Agree with the above, lost count of the number of times my windows won’t join only to find it a hair off in alignment.