I noticed today that this bug eventually has been resolved with the MsgPlus! version 4.80. I know i'm a bit late for noticing this
I tried to reproduce this bug again yesterday but I couldn't. Then I installed the previous versions of Plus! one by one and until version 4.80 I could reproduce it at each time. But couldn't in version 4.80.
I read the changelog of version 4.80 and found out that:
quote:
Originally posted in Changelog of version 4.80
- A couple of things have been improved internally to ensure the reliability of the sound modules in Messenger Plus! (especially when using emotion sounds).
And I think that also solved this problem. I wonder if it has been solved by itself or Patchou intended to solve this also while improving sound modules?
Whatever, people can use the sound-only event notifications after this time without hesitating
/ 
