Hi Bach Pham,
The following two changes correct the specific problems using Firefox. I wish they also corrected the jumping/wrong-helper-positioning using iOS-Safari and Chrome when the page is scrolled, but they do not. So it could be that these changes should not be implemented. But in iOS-Safari and Chrome there is not (and was not) an oops-behavior issue, only a visual issue when the page is scrolled.
There is a long-standing discussion of the jumping/wrong-helper-positioning issue at this link...
stackoverflow.com/questions/5791886/jque...-after-page-scrolled
There is also an old closed bug report at this link...
bugs.jqueryui.com/ticket/3740
It seems that some updates to the jquery-ui interface have solved the visual issue, while later updates have created it again.
The two changes which correct the problem in Firefox are in the file...
\modules\mod_jo_audio_player\assets\js\jquery.html5audio.min.js
(1) Remove oops behavior by invoking the clone option by finding the text...
cursor:"move",
and inserting immediately after the comma...
helper:"clone",
Without this change the helper has the default value of "original" which causes the oops behavior.
(2) Remove issues with jumping/wrong-helper-position in Firefox when the page is scrolled by deleting the following text...
u.bind("sortstart", function(a,b){b.helper.css("margin-top",Md.scrollTop())}),u.bind("sortbeforestop",function(a,b){b.helper.css("margin-top","1px")}),
Perhaps a new thread should be started on the jumping/wrong-helper-position issue in iOS-Safari and Chrome. I do not know if it exists in other browsers too. Or perhaps this thread should be kept open until that issue is also solved - in case the solution to that issue leads to change (2) above being wrong. To me it seems unlikely that change (1) would be affected; but that's just my guess.
Rich