Use Alt-LMB to improve tool-access (when MMB emulation is used, we can't enable this).
- For LCS: Alt-LMB executes the tool without needing to use the gizmo.
(we keep drag threshold as it's needed for detecting selection).
- For RCS: Alt-LMB sets the cursor.
(this allows us to remove the drag threshold on LMB - it always activates tool immediately).
### Conflicts
- Regarding use of Alt-LMB, see {T69323} for possible conflicts.
### Open Topics
- Some tools use the Alt key - such as shrink-fatten.
Possible solutions:
- Modal operators that use Alt will have to ignore the alt key on tool activation, then detect it on release and press.
- The alt key behavior could be inverted when it's used for activation.
- Requiring Alt-LMB to set the 3D cursor when tools are activated might not be preferred by some users.
Possible solutions:
- Keep the drag threshold for the tweak tool (perhaps all selection tools), so by default LMB-click places the cursor.
- Have a preference to keep the current behavior - which uses a drag threshold to allow cursor placement and tools that drag.
- Does this apply to other editors - spesifically time-line editors with tools (the sequencer for e.g.). Most likely placing the current frame with Alt-LMB isn't desirable, so we could opt-out of this in some cases (needs some further investigation).