Here’s an example of what I mean:
Suppose I added a LUT filter to a clip. If I’m not satisfied with the one I chose, I click the Open button again and Shotcut goes back to the last folder I used.
Now suppose later I want to edit I bunch of transitions with custom images or clips. I select a transition, go to Properties > Video menu > Custom and Shotcut takes me back to the LUT folder I used earlier.
I navigate to the folder where I store my custom transition files and pick one. Then I go to edit the next transition and Shotcut takes me AGAIN to the LUT folder. And again for the next transition…
Same goes with the Mask: From File filter. Shotcut will remember the last folder used with this filter. But if go edit more transitions, Shotcut will constantly go back to the folder used by Mask: From File.
So, my suggestion is to make Properties> Video menu > Custom remember the last path it used.
Add an option in Settings to set default paths for each tool that requires to open a folder to fetch a file.