PlugPopup : Improve handling of textWidgets

Look for `textWidget()` attr rather than specific classes, so we can find `GafferSceneUI.SetExpressionPlugValueWidget`. Connect to `activatedSignal()` so we can close automatically when <kbd>Ctrl</kbd>+<kbd>Enter</kbd> is pressed in MultiLineTextWidgets.

python/GafferUI/PlugPopup.py

@@ -116,6 +116,7 @@ def __init__( self, plugs, title = None, warning = None, **kw ) :
 			colorPlugValueWidget.setColorChooserVisible( True )
 
 		self.visibilityChangedSignal().connect( Gaffer.WeakMethod( self.__visibilityChanged ), scoped = False )
+		self.focusChangedSignal().connect( Gaffer.WeakMethod( self.__focusChanged ), scoped = False )
 
 	def popup( self, center = None ) :
 
@@ -154,6 +155,19 @@ def __visibilityChanged( self, unused ) :
 			if gafferWidget is not None and self.isAncestorOf( gafferWidget ) :
 				gafferWidget._qtWidget().clearFocus()
 
+	def __focusChanged( self, oldWidget, newWidget ) :
+
+		if self.__plugValueWidget.isAncestorOf( newWidget ) and hasattr( newWidget, "activatedSignal" ) :
+			self.__widgetActivatedConnection = newWidget.activatedSignal().connect(
+				Gaffer.WeakMethod( self.__activated ), scoped = True
+			)
+		else :
+			self.__widgetActivatedConnection = None
+
+	def __activated( self, unused ) :
+
+		self.close()
+
 	@classmethod
 	def __firstTextWidget( cls, plugValueWidget ) :
 
@@ -165,13 +179,11 @@ def widgetUsable( w ) :
 
 		widget = None
 
-		if isinstance( plugValueWidget, GafferUI.StringPlugValueWidget ) :
-			widget = plugValueWidget.textWidget()
-		elif isinstance( plugValueWidget, GafferUI.NumericPlugValueWidget ) :
+		if isinstance( plugValueWidget, GafferUI.NumericPlugValueWidget ) :
 			widget = plugValueWidget.numericWidget()
 		elif isinstance( plugValueWidget, GafferUI.PathPlugValueWidget ) :
 			widget = plugValueWidget.pathWidget()
-		elif isinstance( plugValueWidget, GafferUI.MultiLineStringPlugValueWidget ) :
+		elif hasattr( plugValueWidget, "textWidget" ) :
 			widget = plugValueWidget.textWidget()
 
 		if widget is not None and widgetUsable( widget ) :