You have lost the Tool options dialog. See here how to restore it and keep it around
Once you have recovered it, the little square near the pointer ( ) says that he tool is set to move the selection mask:
For what you want to do, the proper setting is Move: Layer:
Once you have recovered it, the little square near the pointer ( ) says that he tool is set to move the selection mask:
For what you want to do, the proper setting is Move: Layer: