I am not sure when this minor bug showed up, but I am currently using beta2-109 on a Mac, and I see it.
If I open OM, and leave it on the default screen, I don't see the problem.
On the other hand, if I move it to the external monitor, and open a few plot windows, when I click on the modeling tab, then click back on plotting, the plots are all invisible. It is easy to get them back, because the problem is just that the frame that the plots are in is too wide for the space. So, I just need to move the scroll bar to see them. But, if I click Modeling, and then click back to plotting, they are again off the screen. So, every time I click back to plotting, I have to scroll to see the plots.
Because this was a bit tricky to describe with words, I have attached two screen grabs.
Note that when I just leave OM on the primary internal monitor, that I don't even see a horizontal scroll bar. The inner panel is a fixed size. But, when I move it to the other screen OM "thinks" that the inner panel, where it shows the plots, is big, adds the scroll bar and then moves defaults all the way to the rights so they are off of this panel.
Windows "hidden" off edge of panel