Minor bug in ListGrid drag'n'drop - latest nightly

[ect]

Version: SC_SNAPSHOT-2011-07-21/LGPL Development Only (built 2011-07-21)

Steps to reproduce:
1) open feature explorer
2) open "Drag & Drop" -> "Drag tree (move)"
3) switch to tab "example Data"
4) disable the tree nodes of "partsTree2":

isc.Tree.create({ID:"partsTree2", root:{children:[
    {name:"Bin 3", children:[
        {name:"Blue Part", icon:"piece_blue.png", enabled: false},
        {name:"Green Part", icon:"piece_green.png", enabled: false},
        {name:"Yellow Part", icon:"piece_yellow.png", enabled: false}
    ]}
]}})

5) Try it
6) Drag a piece from the left hand side and move it onto the "Green Part" on the right hand side
7) js error is thrown:

09:48:46.303:TMR5:WARN:Log:TypeError: this._dragLine is undefined
    ListGrid.showDragLineForRecord(_1=>2,  _2=>"after", undefined=>undef, undefined=>undef, undefined=>undef, undefined=>undef, undefined=>undef, undefined=>undef)
    Class.invokeSuper(_1=>{Obj},  _2=>"showDragLineForRecord",  _3=>2,  _4=>"after",  _5=>undef,  _6=>undef,  _7=>undef)
    TreeGrid.showDragLineForRecord(2, "after")
    TreeGrid.dropMove({Obj}, undef)
    [c]EventHandler.bubbleEvent(_1=>{Obj},  _2=>"dropMove",  _3=>undef)
    [c]EventHandler.handleEvent(_1=>{Obj},  _2=>"dropMove")
    [c]EventHandler.handleDragMove()
    EventHandler.._handleMouseMove(null, {Obj})
    EventHandler._handleMouseMove(null, {Obj})
    EventHandler._delayedMouseMove(1311320926278)
    [c]Class.fireCallback(_1=>{Obj},  _2=>undef,  _3=>[object Array],  _4=>{Obj},  _5=>true)
    Timer._fireTimeout("$ir2760")
    unnamed()
    unnamed() @

8) Once you move the piece above or below the disabled nodes, the _dragLine is there and the error disappears
9) Resolution:
in "showDragLineForRecord", change

if (!this.recordIsEnabled(recordNum) && recordNum != lastVisibleRow) return this._dragLine.hide();

to

if (this._dragLine && !this.recordIsEnabled(recordNum) && recordNum != lastVisibleRow) return this._dragLine.hide();

[Isomorphic]

So this basically happens dragging into a grid with all records disabled. Thanks for the fix.