ouch...this kind of method is why i chose to start from scratch…. what is the err you get? Fernando On Sun, Feb 5, 2012 at 6:13 PM, Stéphane Ducasse <stephane.ducasse@inria.fr> wrote:

Hi guys

In 1.4 I get from time to time a problem with

PluggableListMorph>>startDrag: evt        |row ddm draggedItem draggedItemMorph |

       dragItemSelector ifNotNil: [ ^self startDragExtended: evt ].        evt hand hasSubmorphs ifTrue: [^ self].        (self dragEnabled and: [model okToChange]) ifFalse: [^ self].

       (row := self mouseDownRow)                ifNil: [ draggedItem := self getListItem: lastNonZeroIndex. "self selection" ]

                                                                               where lastNonZeroIndex is nil

               ifNotNil: [ draggedItem := self getListItem: row ].

       "Here I ensureat least one element is selected "        draggedItem ifNil: [ ^ self ].

       self isMultipleSelection                ifTrue: [ | passengers |                        passengers := self model dragPassengersFor: draggedItem inMorph: self.                        passengers ifNil: [ ^ self ].                        draggedItemMorph := StringMorph contents: (passengers joinUsing: ' ') asStringOrText.                        ddm := TransferMorph withPassenger: passengers from: self ]                ifFalse: [ | passenger |                        passenger := self model dragPassengerFor: draggedItem inMorph: self.                        passenger ifNil: [ ^ self ].                        draggedItemMorph := StringMorph contents: passenger asStringOrText.                        ddm := TransferMorph withPassenger: passenger from: self ].

       self mouseDownRow: nil.

       ddm dragTransferType: (self model dragTransferTypeForMorph: self).

       [evt hand grabMorph: ddm ] ensure: [                                                                                Cursor normal show.                                                                                evt hand releaseMouseFocus: self]

listSelectionAt: index

       index isZero ifFalse:[ lastNonZeroIndex := index ].        getSelectionListSelector ifNil:[^false].        ^model perform: getSelectionListSelector with: index

So it looks like there are path where lastNonZeroIndex can be nil.