I have edited the _mdi_menu to change the hotkey for the Tools menu to 'o' (changed Caption from &Tools to T&ools). My normal SlickEdit session does let me use Alt, O to open this menu. I just noticed when I open a new SlickEdit instance from the Organize All Workspaces/New Instance button, the Tools menu reverts to the default 't' hotkey.
I tried to reproduce this behavior starting from the default config, but when I start with a default config and edit the _mdi_menu to change &Tools to T&ools, the menu does not change. The change is saved to the userMenus.xml file though. Perhaps both of these issues are the same?
I'm running SlickEdit 25.0.1 (with hotfix_se2501_6...) on Windows 10.