Your comments

I love to see people collaborating positively and finding solutions to make better things.
I like the idea, I don't like very much the jEdit widget graphic.
Did you know something implementation less intrusive (I like the minimalistic ST2 UI)?.
Maybe good to have it as a preference, that the user can toggle on his personal choice.
Good idea. May help seeing a mockup to compare the two solutions.

Anyway, I think it's soon to discuss on this marginal detail.

Oh thanks, that's great! I was not aware of that discussion... I searched the wrong keywords...
I'll follow your suggestion and I'll post there.
Thanks again for your time.
I apologize for the late response, it has been a busy week.

I considered with great attention your comments and I prepared some sheets to analyze the current and eventually future UI development.

Point 1) Usability standpoint:

Point 2) Window dragging:

In addition to these considerations, I reasoned over the multi-rows/multi-columns layout.
No problem here too.
The top bar cab be splitted in two segments, as happens now in ST, to make room for the two or more columns.
The tabs on the second (or more) row still remain placed on a tab bar with a dark background like current implementation. Just an adjustment to make the bars of the same height of the top uni-bar.