selection-inhibit-update-commands

selection-inhibit-update-commands is a variable defined in `C source code'.
Its value is

(handle-switch-frame handle-select-window)

• This variable may be risky if used as a file-local variable.

Documentation:
List of commands which should not update the selection.
Normally, if `select-active-regions' is non-nil and the mark remains
active after a command (i.e. the mark was not deactivated), the Emacs
command loop sets the selection to the text in the region. However,
if the command is in this list, the selection is not updated.