To reproduce the issue:
1) Open a file that is controlled under Git
2) Version Control > History Diff for ...
3) Right click in the editor control
Stack trace written to file: /tmp/vsstack.XXXXXX
Control -ctlfile1-readonly referenced but does not exist
diffedit.ex 4632 diffedit:edit_window_rbutton_up() p_window_id: 337 p_object: OI_EDITOR p_name: _ctlfile1 form_name: _history_diff_form
diffedit.ex 11218 diffedit:_EditControlEventHandler() p_window_id: 337 p_object: OI_EDITOR p_name: _ctlfile1 form_name: _history_diff_form
diffedit.ex 12808 _diff_form._ctlfile1.range_first_nonchar_key-all_range_last_nonchar_key() p_window_id: 337 p_object: OI_EDITOR p_name: _ctlfile1 form_name: _history_diff_form
dlgeditv.ex 7514 show(-modal -xy _history_diff_form,@24462,eeddced489df362b22fafcbfa1b31aa7a96e1403,0) p_window_id: 459 p_object: OI_MINIHTML p_name: ctlminihtml1 form_name: _svc_query_output_form
svc.ex 17573 svc_history_diff(/home/XXXXXXXX.local/XXXXXX/.../XXXXXXX.cpp,,eeddced489df362b22fafcbfa1b31aa7a96e1403,1)
p_window_id: 530
p_object: OI_EDITOR
p_name:
svcquery.ex 3603 _svc_query_output_form.ctlminihtml1.on_change(32,histdiff:eeddced489df362b22fafcbfa1b31aa7a96e1403) p_window_id: 530 p_object: OI_EDITOR p_name:
controls.ex 1444 _ul2_minihtm.lbutton_down() p_window_id: 530 p_object: OI_EDITOR p_name:
There is no "_ctlfile1_readonly" control is on the history diff form. The right click handler should check if it's there before using it.