colReorder drag events are triggered with any mouse click

This leads to an issue with chromium which can be reproduced in the following manner:

• Open a table using colReorder
• Left click on any column header to show the context menu
• Press escape to exit out of the context menu.
• You are now stuck with a dragable column in your cursor.

The fix is as simple as only allowing fro drag and drop events when a left mouse button click is registered. Code change. A more complex fix might be necessary if being able to initiate drag and drop events with any mouse button click is deemed a feature and not a bug.

Best Regards,
Pedro