Pop-up and give focus to the label editor.

        position MUST be in global coordinates.

def newShape(self):
        """Pop-up and give focus to the label editor.

        position MUST be in global coordinates.
        """
        if not self.useDefaultLabelCheckbox.isChecked() or not self.defaultLabelTextLine.text():
            if len(self.labelHist) > 0:
                self.labelDialog = LabelDialog(
                    parent=self, listItem=self.labelHist)

            # Sync single class mode from PR#106
            if self.singleClassMode.isChecked() and self.lastLabel:
                text = self.lastLabel
            else:
                text = self.labelDialog.popUp(text=self.prevLabelText)
                self.lastLabel = text
        else:
            text = self.defaultLabelTextLine.text()

        # Add Chris
        self.diffcButton.setChecked(False)
        if text is not None:
            self.prevLabelText = text
            generate_color = generateColorByText(text)
            shape = self.canvas.setLastLabel(text, generate_color, generate_color)
            self.addLabel(shape)
            if self.beginner():  # Switch to edit mode.
                self.canvas.setEditing(True)
                self.actions.create.setEnabled(True)
            else:
                self.actions.editMode.setEnabled(True)
            self.setDirty()

            if text not in self.labelHist:
                self.labelHist.append(text)
        else:
            # self.canvas.undoLastLine()
            self.canvas.resetAllLines()