Little glitch with DnD?

Try to drag'n'drop something to another tab, with folder on another disk.
Does + sign disappear for you, if you press shift before dropping?

X.

No it does not. In addition, if the folder tab you're trying to drop a file to is located on the same disk as the source file is located on, the role of the [shift] key gets reversed (meaning, without holding [shift] the file gets moved as expected, but if you hold down [shift] a copy will be made instead).

Time for a bug report perhaps?