@bool check_for_changed_external_files may hang on network files

[JohnLunzer]

With the current implementation Leo can become unresponsive in some environments. Implementing the checking logic in non-blocking threads or a separate process could mitigate any negative performance impact.

Additionally, if the Leo window is inactive withhold all notifications until Leo becomes active again.

Please see this Leo conversation for reference.

[edreamleo]

Rev 4373f88 attempts to fix #262 by checking at most one commander during idle time.

This approach could be extended by checking only one @ node at idle time, but that might result in long delays between checks of an @ node.

Please let me know if the fix works for you.

[edreamleo]

I am reopening this issue and marking it as a bug because of serious problems when using network drives.

[edreamleo]

Rev 2a0eca1: set the default setting for @Bool check_for_changed_external_files to False. The comment in the body text of the setting's node references this issue.

Given the potential severity of this bug, I think it's important that people must explicitly enable this feature. It will prevent future reports that Leo has become broken.

[edreamleo]

It's time to close this issue. I see no reason to leave this issue open indefinitely.

@bool check_for_changed_external_files in leoSettings.leo defaults to False, so it can be said to be safe by default. Furthermore it contains an adequate warning, and references this issue.