Fix ROI.sigRemoveClicked to avoid repeated signal emission

Update ROI example to demonstrate removal

examples/ROIExamples.py

@@ -132,7 +132,7 @@ label4 = w4.addLabel(text, row=0, col=0)
 v4 = w4.addViewBox(row=1, col=0, lockAspect=True)
 g = pg.GridItem()
 v4.addItem(g)
-r4 = pg.ROI([0,0], [100,100])
+r4 = pg.ROI([0,0], [100,100], removable=True)
 r4.addRotateHandle([1,0], [0.5, 0.5])
 r4.addRotateHandle([0,1], [0.5, 0.5])
 img4 = pg.ImageItem(arr)
@@ -142,6 +142,12 @@ img4.setParentItem(r4)
 v4.disableAutoRange('xy')
 v4.autoRange()
 
+# Provide a callback to remove the ROI (and its children) when
+# "remove" is selected from the context menu.
+def remove():
+    v4.removeItem(r4)
+r4.sigRemoveRequested.connect(remove)
+
 
 
 

pyqtgraph/graphicsItems/ROI.py

@@ -665,9 +665,7 @@ class ROI(GraphicsObject):
 
     def removeClicked(self):
         ## Send remove event only after we have exited the menu event handler
-        self.removeTimer = QtCore.QTimer()
-        self.removeTimer.timeout.connect(lambda: self.sigRemoveRequested.emit(self))
-        self.removeTimer.start(0)
+        QtCore.QTimer.singleShot(0, lambda: self.sigRemoveRequested.emit(self))
         
     def mouseDragEvent(self, ev):
         if ev.isStart():