--- a/PanelView.st	Tue Dec 17 16:39:10 2019 +0100
+++ b/PanelView.st	Tue Dec 17 16:40:54 2019 +0100
@@ -309,6 +309,59 @@
     "Created: / 30.3.1999 / 13:48:42 / stefan"
 ! !
 
+!PanelView methodsFor:'accessing-visibility'!
+
+beVisible
+    "after making the views visible check the vertical layout"
+
+    super beVisible.
+
+    (realized and:[OperatingSystem isMSWINDOWSlike])
+        ifFalse:[ ^ self ].
+
+    (self class == HorizontalPanelView or:[self class == VerticalPanelView]) ifTrue:[
+        self sensor enqueueMessage:#beVisiblePostUpdate for:self.
+    ].
+!
+
+beVisiblePostUpdate
+    "after making the views visible check the vertical layout; called by #beVisible"
+    | sviews |
+
+    (subViews size > 0 and:[self isVisible]) ifFalse:[ ^ self ].
+
+    sviews := self subViewsToConsider.
+    sviews notEmptyOrNil ifTrue:[
+        sviews detect:[: each | (each isView and:[(each getAttribute:#VerticalPanelPreferredWidthOrHeight) isNil]) ]
+            ifNone:[
+               sviews do:[: eachChild |
+                    eachChild isView ifTrue:[  |wh|
+                        wh := eachChild getAttribute:#VerticalPanelPreferredWidthOrHeight.
+                        wh notNil ifTrue:[
+                            self class == VerticalPanelView
+                                ifTrue: [ eachChild height: wh ]
+                                ifFalse:[ eachChild  width: wh ].
+                        ].
+                    ].
+            ].
+            self setChildPositions.
+            mustRearrange := false.
+        ].
+    ].
+    subViews do:[: eachChild |
+        eachChild isView ifTrue:[ eachChild setAttribute: #VerticalPanelPreferredWidthOrHeight to: nil ]
+    ].
+!
+
+storePreferredWidthOrHeight: aWidthOrHeight for: aView
+    "called by UISpecification #buildViewWithLayoutFor to setup up a specific view"
+
+    OperatingSystem isMSWINDOWSlike ifFalse:[ ^ self ].   "/ supported only for windows!!!!
+
+    (aView isView and:[aWidthOrHeight isInteger and:[aWidthOrHeight > 0]])
+        ifTrue:[ aView setAttribute:#VerticalPanelPreferredWidthOrHeight to: aWidthOrHeight ].  "/ see: #beVisiblePostUpdate
+! !
+
 !PanelView methodsFor:'adding & removing subviews'!
 
 addComponent:aComponent