bugfixes (#188)

Bugfixes for several issues: closes #163, closes #151, closes #176, closes #138, closes #104

Co-authored-by: Dominik Demuth <dominik.demuth@physik.tu-darmstadt.de>
Reviewed-on: #188

src/gui_qt/lib/mdiarea.py

@@ -7,8 +7,11 @@ from ..graphs.graphwindow import QGraphWindow
 
 
 class MdiAreaTile(QtWidgets.QMdiArea):
+    newData = QtCore.pyqtSignal(list)
+
     def __init__(self, parent=None):
         super().__init__(parent=parent)
+        self.setAcceptDrops(True)
 
     def tileSubWindowsVertically(self):
         window_list = self.subWindowList()
@@ -47,3 +50,8 @@ class MdiAreaTile(QtWidgets.QMdiArea):
             if isinstance(wdgt, QGraphWindow) and wdgt.id == key:
                 self.setActiveSubWindow(win)
                 break
+
+    def dropEvent(self, evt):
+        if evt.mimeData().hasUrls():
+            files = [str(url.toLocalFile()) for url in evt.mimeData().urls()]
+            self.newData.emit(files)