Simple patch to MultiCall which stops IDLE's config dialog from crashing upon OK/Apply.

The bug is caused by ConfigDialog calling event_add() for key bindings only if there are sequences to be bound, while event_delete() is called even if there are no sequences. This causes MultiCall's internal dictionary of virtual events to raise a KeyError when event_delete() is called with a virtual event, for which event_add() was not called.

The Best Thing IMO is to have MultiCall check if such an event exists in its internal dict, and if not - just ignore the event_delete() call.

Patch attached.

Just to be clear - the bug is that writing certain things in the extension config file (either the user file or the defaults file) causes IDLE's configuration handling mechanism to crash. One symptom is that IDLE's config dialog doesn't save or apply changes, and is therefore useless.

The bug occurs when a config option without a value is added under a *_bindings or *_cfgBindings section in the extensions config file.

This bug is a result of an assumption in the design of MultiCall which is not true in this case.

Committed in rev. 54156, 54157 (2.5).