--- a/TabView.st	Tue Jan 20 19:13:22 1998 +0100
+++ b/TabView.st	Tue Jan 20 20:00:34 1998 +0100
@@ -14,7 +14,7 @@
 View subclass:#TabView
 	instanceVariableNames:'list listHolder selection enabled action tabStyle useIndex
 		maxRawNr direction fitLastRow moveSelectedRow enableChannel
-		oldExtent oneTabPerLine'
+		selectConditionBlock oldExtent oneTabPerLine'
 	classVariableNames:''
 	poolDictionaries:''
 	category:'Views-Interactors'
@@ -346,6 +346,22 @@
     self enabled:aState
 
 
+!
+
+selectConditionBlock
+    "get the conditionBlock; this block is evaluated before a selection
+     change is performed; the change will not be done, if the evaluation
+     returns false. The argument to the block is the selection index
+    "
+    ^ selectConditionBlock
+!
+
+selectConditionBlock:aOneArgBlock
+    "get the conditionBlock; this block is evaluated before a selection
+     change is performed; the change will not be done, if the evaluation
+     returns false. The argument to the block is the selection index
+    "
+    selectConditionBlock := aOneArgBlock
 ! !
 
 !TabView methodsFor:'accessing channels/holders'!
@@ -759,41 +775,61 @@
 keyPress:aKey x:x y:y
     "selection might change; look for corresponding list entry
     "
-    |size newSel index|
+    |size index n|
+
+    (self isEnabled and:[(size := list size) > 1]) ifFalse:[
+        ^ self
+    ].
 
-    (self isEnabled and:[(size := list size) ~~ 0]) ifTrue:[
-        (aKey == #CursorRight or:[aKey == #CursorDown]) ifTrue:[
-            (selection isNil or:[selection == size]) ifTrue:[
-                newSel := 1
-            ] ifFalse:[
-                newSel := (selection + 1)
+    (aKey == #CursorRight or:[aKey == #CursorDown]) ifTrue:[
+        n := selection ? 0.
+        (size - 1) timesRepeat:[
+            (n := n + 1) > size ifTrue:[n := 1].
+
+            (selectConditionBlock isNil or:[selectConditionBlock value:n]) ifTrue:[
+                ^ self selection:n
             ]
-        ] ifFalse:[
-            (aKey == #CursorLeft or:[aKey == #CursorUp]) ifTrue:[
-                (selection isNil or:[selection == 1]) ifTrue:[
-                    newSel := size
-                ] ifFalse:[
-                    newSel := (selection - 1)
+        ].
+        ^ self
+    ].
+
+    (aKey == #CursorLeft or:[aKey == #CursorUp]) ifTrue:[
+        n := selection ? size.
+        (size - 1) timesRepeat:[
+            (n := n - 1) < 1 ifTrue:[n := size].
+
+            (selectConditionBlock isNil or:[selectConditionBlock value:n]) ifTrue:[
+                ^ self selection:n
+            ]
+        ].
+        ^ self
+    ].
+
+    aKey isCharacter ifTrue:[
+        (selection isNil or:[selection == size]) ifTrue:[index := 1]
+                                                ifFalse:[index := selection + 1].
+
+        n := index - 1.
+        [   
+            n := self findTabStartingWithKey:aKey startingAt:n + 1.
+
+            n ~~ 0 ifTrue:[
+                (selectConditionBlock isNil or:[selectConditionBlock value:n]) ifTrue:[
+                    ^ self selection:n
                 ]
-            ] ifFalse:[
-                aKey isCharacter ifTrue:[
-                    (selection isNil or:[selection == size]) ifTrue:[index := 1]
-                                                            ifFalse:[index := selection + 1].
-                    newSel := self findTabStartingWithKey:aKey startingAt:index.
+            ].
+            n ~~ 0
 
-                    (newSel == 0 and:[index ~~ 1]) ifTrue:[
-                        newSel := self findTabStartingWithKey:aKey startingAt:1
-                    ]
-                ]
+        ] whileTrue.
+
+        index ~~ 1 ifTrue:[
+            (n := self findTabStartingWithKey:aKey startingAt:1) ~~ 0 ifTrue:[
+                ^ self selection:n
             ]
         ]
     ].
 
-    (newSel isNil or:[newSel == 0]) ifTrue:[
-        super keyPress:aKey x:x y:y
-    ].
-    self selection:newSel
-
+    super keyPress:aKey x:x y:y
 ! !
 
 !TabView methodsFor:'initialization'!
@@ -1076,6 +1112,18 @@
 
 !
 
+isTabSelectable:aTab
+    "returns true if tab is selectable
+    "
+    self isEnabled ifTrue:[
+        selectConditionBlock notNil ifTrue:[
+            ^ selectConditionBlock value:(list identityIndexOf:aTab)
+        ].
+        ^ true
+    ].
+    ^ false
+!
+
 isVerticalDirection
     "returns true in case of direction is #left or #right
     "
@@ -1129,8 +1177,15 @@
     list size == 0 ifTrue:[^ self].
     newSel := self listIndexOf:something.
     selection == newSel ifTrue:[^ self].
+
     newSel notNil ifTrue:[
-        (newSel between:1 and:list size) ifFalse:[newSel := nil].
+        (newSel between:1 and:list size) ifFalse:[
+            newSel := nil
+        ] ifTrue:[
+            selectConditionBlock notNil ifTrue:[
+                (selectConditionBlock value:newSel) ifFalse:[^ self]
+            ]
+        ]
     ].
 
     self shown ifFalse:[
@@ -1200,5 +1255,5 @@
 !TabView class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libwidg2/TabView.st,v 1.29 1997-11-02 18:28:49 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libwidg2/TabView.st,v 1.30 1998-01-20 19:00:21 ca Exp $'
 ! !

--- a/TabWidget.st	Tue Jan 20 19:13:22 1998 +0100
+++ b/TabWidget.st	Tue Jan 20 20:00:34 1998 +0100
@@ -382,7 +382,7 @@
 setLabelColor
     "set the label color dependant on the enabled state of the tabView
     "
-    tabView isEnabled ifTrue:[
+    (tabView isTabSelectable:self) ifTrue:[
         tabView paintColor:#labelColor.
     ] ifFalse:[
         tabView paintColor:#shadowColorUnselected.
@@ -998,5 +998,5 @@
 !TabWidget class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libwidg2/TabWidget.st,v 1.12 1997-10-11 12:20:07 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libwidg2/TabWidget.st,v 1.13 1998-01-20 19:00:34 ca Exp $'
 ! !