In the case when you have an issue with the dropzone in IceWarp WebClient PRO
as a workaround please extract the attached archive to \IceWarp\html\webmail\client\inc
Then you have to navigate to \IceWarp\html\webmail there you have to run "build.safe" file using "php.exe" in IceWarp PHP folder (\IceWarp\php)
For Linux is necessary to define CLIENT class.
NOTE: Fix for https://icewarp.zendesk.com/hc/en-us/articles/115007591387-Autoresponder-date-differences-between-client-and-console is also included in the archive.