What is your Shotcut version (see Help > About Shotcut)? Is it 32-bit?
Can you repeat the problem? If so, what are the steps?
(Please be specific and use the names as seen in Shotcut, preferably English. Include a screenshot or screen recording if you can. Also, you can attach logs from either View > Application Log or right-click a job and choose View Log.)
Add Filter Text:Rich
Select Preset: Scroll left
The entire text box jumps to the middle left and all other options gray out.
Depending on where the playhead is in the clip, this is to be expected.
The only part that is grayed out is the Position and Background size.
If you want to change the size of the box, select (defaults) at the top of the list of presets, make your adjustments then select Scroll left again.
Everything else is fully functional in the filter.
When you choose the “Scroll Left” preset, Shotcut enables simple animations and sets the position to the far right at the beginning of the clip and the far left at the end of the clip. Shotcut then interpolates the position between the beginning and the end. When simple animations are enabled, you can only edit the parameters when the cursor position is at the beginning or the end (because Shotcut will interpolate the middle values you can not edit them.
So yes, this is on purpose. And I suppose it is a little tricky the first time. If you want to edit the parameters, seek to the beginning or end of the clip to edit them.