I'd recommend not trying to widen the topic properties panel on the right side of RH2019.
Mostly it refuses to move, but if you succeed in grabbing it, you'll copy the text and buttons from the panel into your open topic. ('scuse the green background. I was trying to troubleshoot my stylesheet.)
I still can't expand the panel, but the most I managed to drag into my topic was a <br /> so that's an improvement.
While we're here, what do "click to link" and "click to unlink" mean?
In linked state, all values are in sync. If you change the margin in one field, other 3 will also change. In unlinked state, all 4 fields can have different values.
We need to look at your screen and see why resize of the Properties panel is not happening.
Thanks for the link description. You should probably include that in the help .
I found out why the panel doesn't work. It doesn't work on secondary monitors, only the main monitor. I also listed this as a bug for the colour picker, which only works on the main monitor.