--- a/extensions.st	Fri Feb 12 22:31:59 2016 +0100
+++ b/extensions.st	Sat Feb 13 12:24:44 2016 +0100
@@ -22,6 +22,8 @@
 !AbstractTime class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     ^ #timeClassBrowserIcon
@@ -117,7 +119,8 @@
 
 iconInBrowserSymbol
     "can be redefined for a private icon in the browser (for me and my subclasses).
-     The returned symbol must be a selector of the ToolbarIconLibrary."
+     The returned symbol must be a selector of the ToolbarIconLibrary.
+     The browser will use this as index into the toolbariconlibrary"
 
     <resource: #programImage>
 
@@ -614,8 +617,13 @@
 !Collection class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+    
     <resource: #programImage>
 
+    self isAbstract ifTrue:[
+        ^ #abstractContainerClassBrowserIcon
+    ].    
     ^ #containerClassBrowserIcon
 ! !
 
@@ -709,6 +717,8 @@
 !Date class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     ^ #timeClassBrowserIcon
@@ -805,6 +815,8 @@
 !Error class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     ^ #errorClassBrowserIcon
@@ -897,6 +909,8 @@
 !GenericException class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     ^ #exceptionClassBrowserIcon
@@ -1275,6 +1289,8 @@
 !LibraryDefinition class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     self theNonMetaclass isLibraryDefinition ifTrue:[^ #libraryDefinitionClassIcon ].
@@ -1552,6 +1568,8 @@
 !Notification class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     ^ #notificationClassBrowserIcon
@@ -1895,6 +1913,8 @@
 !ProjectDefinition class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     self theNonMetaclass isApplicationDefinition ifTrue:[
@@ -1909,6 +1929,8 @@
 !Query class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     ^ #queryClassBrowserIcon
@@ -1957,6 +1979,8 @@
 !SharedPool class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     self == SharedPool ifTrue:[^ super iconInBrowserSymbol].
@@ -1988,6 +2012,8 @@
 !SimpleView class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     ^ #windowClassBrowserIcon
@@ -2048,6 +2074,8 @@
 !StandaloneStartup class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     self == StandaloneStartup ifFalse:[
@@ -2824,6 +2852,8 @@
 !Warning class methodsFor:'misc ui support'!
 
 iconInBrowserSymbol
+    "the browser will use this as index into the toolbariconlibrary"
+
     <resource: #programImage>
 
     ^ #warningClassBrowserIcon