In a DAW that I used to use, you could just right-click anywhere in the "row" that has the bar numbers (any window), and an entry box would pop up with the cursor in it, ready for you to type your comment, text etc.

Then just hit Enter to continue working. No slowdown in workflow.

It would also place a small "marker" in that row, in the position where you right clicked. If you needed to edit the text, you simply double clicked on the marker. If you needed to move the marker, you would just drag it to where you needed it.

LLOYD S

OK, I went back to that old DAW just to be sure, and that's not quite how it works.
There is already a "waiting" marker, in the upper left corner of the bar-number row.
You just grab it and drag it where you want it, then up pops the "enter text" box,
PLUS a "Marker time" box you can either type values into, or use the spin buttons
(but you don't need to do either).

The marker itself is just a small triangular shaped "flag" at the top of a line, and when you
drag-and-set it, it puts a "marker line" vertically, all the way through the (say) bars window.