The Tabbed MAXScript Editor introduced in 3ds Max 2008 lets you define your own custom keyboard shortcuts in addition to the hard-coded shortcuts listed in the topic MAXScript Editor - Keyboard Shortcuts
Custom keyboard shortcuts can be defined in the file MXS_Editor.properties which is easily accessible via the Tools > Open Global Options File menu item. See MAXScript Editor - Properties File Settings for all options.
Scroll down and locate the section remarked as
This section contains some existing keyboard shortcut definitions.
and is a '|' delimited list of keys and the commands they produce.
To place each command on a new line, add a backslash \ at the end of each line.
The commands are either strings or numeric IDs - see List of Editor Key Commands and List of Editor Menu Commands.
Numeric IDs above 2000 are Scintilla commands and are sent to the focussed pane.
Named IDs and numeric IDs below 2000 are SciTE menu commands.
The named keys are Left, Right, Up, Down, Insert, End, Home, Enter, Space, Tab, KeypadPlus, KeypadMinus, KeypadMultiply, KeypadDivide, Escape, Delete, PageUp, PageDown, Slash, Question, Equal, Win.
Let’s assume you want to add a keyboard shortcut for the editor feature "Clear All Bookmarks". This feature is listed in the Search menu but does not have a keyboard shortcut assigned.
Locate in the List of Named IDs the one called "IDM_BOOKMARK_CLEARALL". Since all existing Bookmark-related shortcuts use the Function Key F2 , let's assign the keyboard shortcut Ctrl+SHIFT+F2 to the Clear All Bookmarks feature by adding to the user.shortcuts definition in the MXS_Editor.properties file:
Open the Editor, load a script file and set several bookmarks using Ctrl+F2.
Hold down Ctrl and SHIFT and press F2 - all bookmarks will be cleared!