drag file between personal folder and groupfolder
draw drag dropDestination
drag file from groupTrash to groupFolder
create doc in folderItem and groupItem
 copy doc && download progress
copy document
drop doc at groupRootItem
dragHover expand
dragItem expand
groupTrash don't accept drop
copy doc. keep create and modify time same as sourceDoc.
create doc in trash
make sure file exits before copy
sync use independent database
Merge branch 'v2.1.1' into testing
copy doc with binary
copy doc
different connection to same db file could lock each other.
edit comment
correct function name