Default the 3D editor to Transform mode to restore 4.5 behavior

[Calinou]

The Select mode no longer allows moving or rotating selected nodes. This mode was still the default until now, which results in behavior that's inconsistent with the 2D editor.

This sets the default mode to the new Transform mode to ensure usability out of the box is unchanged. Shortcuts and icon ordering were also modified to best match 4.5.

In a future PR, we could consider persisting the last used mode across editor sessions (using scene metadata), but this has some caveats:

• The mode would now be toggled on a per-scene basis, rather than globally.
• If someone restarts the editor to fix manipulation gizmos not appearing (after accidentally pressing Q), it wouldn't save them anymore.

Preview

3d_editor_transform_mode_default_2.mp4

Old version

3d_editor_transform_mode_default.mp4

[fire]

Did not technical review, but the concept of keeping the same defaults as a previous version makes sense.

[akien-mga]

It seems a bit weird to have the default selected action not being the first one, and the Q-W-E-R hotkeys no longer match the order of the icons (which is what they were meant to do).

Edit: I checked the code and Q-W-E-R hotkeys still match the order of the icons, as Q is still assigned to the first icon (now the Select mode, different from the 4.5 Transform-named-Select mode). The new Transform icon is assigned to V. So users used to using Q for transformation might be annoyed by the change. But visually the order is fine.

So maybe we should restore the previous behavior/icon by default, and use a new icon for the new selection behavior.

[Calinou]

Updated per feedback on the contributors chat:

• Transform mode is now on the left, like in 4.5. Its shortcut is now Q to match 4.5 as well.
• Select mode is now the last mode and had its shortcut changed to V.

See OP for an updated video.

[akien-mga]

Looks good to me.

We might want to continue discuss the icons and see whether the icon change will still be jarring to users, but this is good enough for beta1 and we can see what feedback we get.

[akien-mga]

Thanks!