To test:

• Uncomment the debug messages in  tm_window_rep::get_menu_widget
• type a backslash in a TeXmacs document
• Move in and out of the newly created tag in order to see the focus bar change.
• See how the cache misses constantly and grows with each cursor movement.

The reason:

The cache implemented for the toolbars in tm_window_rep::get_menu_widget uses the object returned by a scheme call to menu-expand as a key. Sometimes the object contains "raw" procedures which fail the equality test for the hash.

This happens whenever the menu being expanded contains plain buttons, i.e. when the following scheme syntax is used for a toolbar:

("some label" (some function))

This is the case in the focus-tag-menu when the focus tree has no variants (see generic-menu.scm). The expanded menu then contains "raw" procedures, as in:

("Hybrid" #<procedure #f ()>))

Even if the procedures are the same between two calls, these are not recognized by the equality operator.