Generating Silence error message

When I try to generate silence on the newer version of Audacity, I get an error message “There is not enough room available to paste this selection”. In the past, when I followed the generate silence effect, it inserted the amount time I selected as silence. Any suggestions on solving? Thx.

I dug deeper and found out the reason - had unchecked 2 boxes in the tracks behaviors section under preferences. once i selected the enable dragging section edges and editing a clip can move other clips, generate silence worked.

That’s the one that fixed it. For some bizarre reason that I fail to understand, it was decided last year to change the default from “enabled” to “disabled”.