Is there a way to change inspector to resize when window resizes rather than editor?

Ah, a resize window question that isn’t Catalina related. I’m sure that’s a relief!

When I resize a window with an inspector (usually a PDF or web page in the bookmarks pane) I want my editor to remain the same size but I want the inspector to resize. Currently to resize the inspector it’s a two step process: 1) resize the window to accommodate the expected inspector width, 2) resize the inspector to its new width. Of course vice versa works as well, however it’s still two steps.

I know that this is a small issue but dang if I couldn’t figure out how to do it! Surely some magic key combination while resizing or something, right?

Apologies if this has been asked before. I spent about 30 minutes searching and then started seeing “Try searching again in 3 seconds, try searching again in 8 seconds” and well, that kind of encouraged me to just post the darn question.