I have a similar behaviour in my application: I’m using the onBeforeFileAdd event to get a confirmation from the user that the file to be uploaded does not contain classified information and when returning false to cancel the add operation, it is also not possible to add the same file again (only after a different file has been selected). When the event handler returns true, everything works fine anyway.
I already tried your fix provided in this thread (and even added " || window.dhx4.isIE11" to the location where you did the fix, because I’m using IE11), but the problem still is there.
Note: the issue seems to occur only in “html4” mode of dhtmlxVault (but there regardless whether IE11 is running in native mode or in compatibility mode). Problem is that I need “html4” mode as a fallback because I can’t rely on Flash or Silverlight (or even Html5) be available in used browsers.
I could reproduce the issue using the “04_events/01_add_remove_files.html” example provided with dhtmlxVault Std 2.41, with just two adaptions:
- in “upload_conf.php” I added “mode” => “html4” to force html4 mode
- in the “onBeforeFileAdd” handler I replaced “return true;” by “return confirm(‘Really?’);”
So then when clicking “Cancel” in the confirmation popup, the issue occurs.