I'm getting crashes using an outlineView data source fed by an array of numbers. The crash happens after fiddling around in the view, usually after some variable small delay. Upon crash, the debugger is always stopped in 'class_getSuperclass'. The crash only happens using Integers or Floats over 12. I've simplified it down to this sparse MyDocument class that can be put into a document-based app. Put an outline view into MyDocument.xib and connect the datasource delegate to MyDocument. I'm new at this, so if an experienced MacRubyist can show me what I'm doing wrong, I will be very grateful. thanks, m <<code snippet start>> class MyDocument < NSDocument attr_accessor :dataSourceArray def init super if (self != nil) # Add your subclass-specific initialization here. # If an error occurs here, return nil. end self end def awakeFromNib #@dataSourceArray = [1,2,3,4,5,6,7,8,9,10,11,12] #survives @dataSourceArray = [1,2,3,4,5,6,7,8,9,10,11,12,13] #crashes, anything over 12 #@dataSourceArray = [0.to_i,8.to_i,116.to_i,224.to_i,400.to_i,1000.to_i] #crashes #@dataSourceArray = 13.0 #float also crashes #@dataSourceArray = [10] #survives #@dataSourceArray = [99] #crashes #@dataSourceArray = 99 #crashes #@dataSourceArray = 9 #survives #@dataSourceArray = [NSNumber.numberWithInt(99)] #crashes #@dataSourceArray = Array.new [117] #crashes #@dataSourceArray = [1,2,3,4,[5,6],7,8,9,0] #survives #@dataSourceArray = [0,8,116,224,400,1000] #crashes #@dataSourceArray = [0.to_s,8.to_s,116.to_s,224.to_s,400.to_s,1000.to_s] #survives #@dataSourceArray = [:zero,:eight,:onesixteen,:twotwentyfour,:fourhundred,:hundredyoh] #survives end def windowNibName "MyDocument" end ################## DataSource for OV ####################### def outlineView(outlineView, numberOfChildrenOfItem:item) if item.is_a? Array return item.count end 1 end def outlineView(outlineView, isItemExpandable:item) (item == nil) || ((item.is_a? Array) && (item.count > 0)) end def outlineView(outlineView, child:index, ofItem:item) #returns child item objects if item == nil return @dataSourceArray #root item end if item.is_a? Array return item[index] end return nil end def outlineView(outlineView, objectValueForTableColumn:tableColumn, byItem:item) # returns the object represented by the column at this item item.to_s end end <<code snippet end>>