Fix for unconventional mouse releases while line is dragging

Closes #880

Signed-off-by: falkTX <falktx@falktx.com>

source/frontend/patchcanvas/canvasport.py

@@ -147,6 +147,8 @@ class CanvasPort(QGraphicsItem):
         QGraphicsItem.hoverLeaveEvent(self, event)
 
     def mousePressEvent(self, event):
+        if self.m_mouse_down:
+            self.handleMouseRelease()
         self.m_hover_item = None
         self.m_mouse_down = bool(event.button() == Qt.LeftButton)
         self.m_cursor_moving = False
@@ -209,7 +211,7 @@ class CanvasPort(QGraphicsItem):
 
         self.m_line_mov.updateLinePos(event.scenePos())
 
-    def mouseReleaseEvent(self, event):
+    def handleMouseRelease(self):
         if self.m_mouse_down:
             if self.m_line_mov is not None:
                 item = self.m_line_mov
@@ -265,6 +267,9 @@ class CanvasPort(QGraphicsItem):
         self.m_hover_item = None
         self.m_mouse_down = False
         self.m_cursor_moving = False
+
+    def mouseReleaseEvent(self, event):
+        self.handleMouseRelease()
         QGraphicsItem.mouseReleaseEvent(self, event)
 
     def contextMenuEvent(self, event):

source/frontend/patchcanvas/scene.py

@@ -374,14 +374,11 @@ class PatchScene(QGraphicsScene):
         self.m_mouse_rubberband = False
 
         if event.button() == Qt.MidButton:
-            event.accept()
-
             self.m_mid_button_down = False
 
             # Connection cut mode off
             if self.m_ctrl_down:
                 self.m_view.viewport().unsetCursor()
-            return
 
         QGraphicsScene.mouseReleaseEvent(self, event)