delete time.. not working (related to UNDO bug ?)

Hi,

i use delete time a lot. when i want all a section to move forward in time i just put range and delete.
but sometime (often) it does not work. sometime i found that removing a locked track or remove the divide track list solved it…
but here i’m stuck
i have a session where it’s impossible to “delete time” there’s alot of “inactive tracks” in this session would that be because of that ?
how does that work ?


—EDIT
how… i realise my UNDO is buged again… maybe this explain that.