Add Copy and Paste to add screenshots and files
Copy and paste should be supported in v1.1 and above on desktop using supported browsers: https://github.com/mattermost/platform/blob/master/doc/install/Requirements.md#web-client
As of Firefox 50 this should work now: https://bugzilla.mozilla.org/show_bug.cgi?id=906420
It works in testing on FF Developer Editiion 51.0a2.
Thanks for the note. Pasting images into the text input box is supported on Chrome and Edge. We have a ticket (https://mattermost.atlassian.net/browse/PLT-575) to investigate adding this functionality to Firefix, Safari and IE. The fix is quite complex as these browsers don't support the native method of copying to the clipboard without using a plugin. We've added a known issue to the changelog for the 1.2 release (https://github.com/mattermost/platform/blob/master/CHANGELOG.md#known-issues).
Copy and Paste via Clipboard (on Windows with <Strg + C> and <Strg + V> works for text but not for images like screenshots. Tested with Internet Explorer 11 and Firefox ESR 38.4.0 and Mattermost 1.1.0 build 2920. Drag and Drop is working but this is not Copy and Paste.