Drag-and-drop errors on Weekly View of CalendarPanel

[fabriciomurta]

Issue reported by user on this forum thread: Calendar drag drop problems since svn update

Affected example: http://localhost:51298/#/Calendar/Overview/Basic/

Overview

When using the Calendar in the Week view, drag and drop events triggers JavaScript errors and the page becomes totally unstable.
Initial investigation reveals that the JS error is due to an 'unhandled exception', which should, instead, be an error about the same element being used twice in the page. When ExtJS raises the error, the message is lost somewhere and does not get delivered to the browser's console.

Steps to reproduce

1. Load the Calendar example pointed above
2. Click the 'Week' button on the center-top region of the page
   Some times an error can be triggered at this time. Not always.
3. Drag some intra-daily events (like Haircut, Movies night) around.
   There's not a fixed way to reproduce this issue, but it happens pretty quickly on Chrome
   3.1. Scrolling might help triggering the error.
   3.2. Keep dragging events and scrolling the view until the error triggers.
4. Move daily events a couple days forth and back -- this might trigger the bug as well
   4.1. When moving those events around some may be hidden into the '+ 1 more' label and be no longer draggable -- the same happens on Sencha version.

When the JavaScript error happens, to reset the page to a stable state, it is advisable to refresh the page.

On IE11, the error can be triggered when starting to drag in step 3, and the whole page becomes unresponsive.

Additional information

The ExtJS Calendar example partially reproduces the issue on the weekly view as when there are overlapping.
It has additional issues with overlapping tasks.

Important notice

This might have been introduced with the fix to the example:
http://localhost:51298/#/TreePanel/Advanced/Image_Organizer/

When testing fixes to the dragNdrop in calendar panel, check for potential side effects there.

Checking the other drag and drop examples on drag-drop section is also advised.

[fabriciomurta]

I couldn't find the SVN revision that fixed the Image Organizer sample. Probably was fixed on one of the SVN pack-commits. And there was no changes on the sample itself.

Possibly its r6441 which changes ux/view/Draggable.js.

[DaniilVeriga]

Unfortunately, the current status of Calendar component is going to be a problem. More details on that might be found in this post.

[DaniilVeriga]

For now, I committed the workaround in our Calendar examples in the revision 6496 (SVN trunk). Just to let others seeing it.