Steps:

1. Create new article
2. Go to rich text field
3. Attach image inside rich text

Actual result

Filter panel has 439px width for 1920px screen.

Expected result

Filter panel should take as much space, as possible (so all data fits in).
Number inputs also can be narrower (4 numbers is enough), and than on smallest resolutions panel can be narrower (we have different number range and it takes more space). 
As I checked 250px should be fine (on design we had 280), but not more than 300px for big resolutions.