• I'm honestly not sure the resolution buttons work better. The text will be cutoff by default and unless the panel is very wide, at which point it starts taking up too much space from everything else. And I don't really see D12440 as a solution here, since I'm not sure I agree that dynamic behavior is really what we want here.
• Also, it looks like the buttons are not deactivated if the checkbox in the panel header is turned off?
• I see you added "Clip" as well. Do the settings only apply to the selected/active clip?
• "Directory" is a confusing name for a check-box. It doesn't enable "Directory", it enables custom proxies, right? I'd suggest sticking to labeling the button with what it does.

I'm honestly not sure the resolution buttons work better.

I agree that this point of the patch is the weakest, correctly there are no user interface guidelines for large labels.
For example, we could say if a label is more than 20 characters it should be written on its own line.

Also, it looks like the buttons are not deactivated if the checkbox in the panel header is turned off?

Noted as being something that will need to be updated with the patch.

"Directory" is a confusing name for a check-box. It doesn't enable "Directory", it enables custom proxies, right? I'd suggest sticking to labeling the button with what it does.

This might be confusing since the movie clip editor does not yet support custom proxies as a file but support can be added for this in the future. I still find it nice to keep the layout the same as the Video Sequencer.

I see you added "Clip" as well. Do the settings only apply to the selected/active clip?

Yes, they only apply to the active clip. This addition also matches the proxy settings layout in the Video Sequencer.