Hi!
First of all thank you for such a great program like VLC! I've been using it for a couple of years by now and I really like it!
One thing I've noticed a couple of releases ago, is the strange usage of a toggle button in the control bar. The playlist button doesn't behave the way a user would normally expect it to behave.
This button toggles between two different views: the view in which the video is being displayed and the playlist view in the main screen section. This is nothing special, but the state which currently is being displayed, isn't represented within the button.
Normally the user would expect to have the button to be in the "activated" state, as it is being correctly used for the shuffle and loop buttons. These two buttons are being highlighted in blue. To be consistent, this would be the way to go for the playlist button.
I've noticed this because I wasn't able to find the button to display the video again, after pressing the playlist button. -> I wasn't informed, that the button which I have just pushed, toggled a different view because the button didn't give me this feedback.
Another inconsistency I've found is the following: The equalizer is being opened in a new dialog, whilst the playlist is being represented in the main screen. I can't see any reason, why these two components should behave differently.
Cheers,
an user experience professional