Total Commander

If the Directory tree (Ctrl+F8) is already open ,and I enable "Configuration" -> "Options..." -> "Display" -> "Tree" -> "Always load complete directory tree" - then I have to press Ctrl+F8 (cm_SrcTree) once again before the old-style tree is shown.

The other way around, if I disable "Always load complete directory tree" the new-style tree is shown immediately as expected.

This goes all the way back to TC 7.0

This is intentional and will not be changed. Re-reading the entire tree is very slow, so I do it only on request here.

so I do it only on request here.

I would consider enabling "Always load complete directory tree" to be a request...

I am just imagining a (new) user, trying out features. When he enables "Always load complete directory tree", he will see no change, and not understand that the option also entails that the tree is now only per drive. The next time he switch to Tree view, he might be very surprised, and may not realize that the change he now see is due to the change he made when enabling "Always load complete directory tree", maybe days earlier.