Operating system: Linux-5.8.0-41-generic-x86_64-with-debian-bullseye-sid 64 Bits
Graphics card: AMD STONEY (DRM 3.38.0, 5.8.0-41-generic, LLVM 11.0.0) X.Org 4.5 (Core Profile) Mesa 20.2.6
Broken: version: 2.93.0 Alpha, branch: master, commit date: 2021-02-03 23:01, hash: rBd85c5accecd5 (and version v2.92.0 Beta, same commit date, hash: ebd2aa789e40, *and* version 2.91.2 Release)
Worked: version 2.82a Release
Short description of error
When a Grease Pencil object with multiple strokes is selected in a viewport that isn't in the Draw object interaction mode, there is significant lag to any mouse operation. If the viewport is in Draw mode, or if the offending grease pencil object isn't selected, there is no lag at all.
Exact steps for others to reproduce the error
- Create a new file using any template.
- Add a grease pencil object if one is needed to enter Draw mode. the more strokes it contains, the more pronounced the effect will be.
- Move the view around - there is no lag. It works as expected.
- Change the viewport object interaction mode out of Draw.
- Move/transform the view or the grease pencil object. The viewport will skip frames to catch up.
- Deselect the grease pencil object and move the view around again. The viewport keeps pace with the cursor once again.
Attached is a simple .blend file containing this scenario (2 strokes in one grease pencil object)