code: function(e) {
  			if(this._shouldMoveColumn(e)){
  				this.moveColumn(null, -1);
  				e.preventDefault();
  				return true;
  			}
  			var curModel = this._modelIterator.cursor();
  			if(!curModel){
  				return false;
  			}
  			if(this.isExpandable(curModel)){
  				if(this.isExpanded(curModel)){
  					this.explorer.myTree.collapse(curModel);
  					e.preventDefault();
  					return true;
  				}
  			}
  			if(!this._modelIterator.topLevel(curModel)){
  				this.cursorOn(curModel.parent);
  				this.setSelection(curModel.parent, false, true);
  			//The cursor is now on a top level item which is collapsed. We need to ask the explorer is it wants to scope up.	
  			} else if (this.explorer.scopeUp && typeof this.explorer.scopeUp === "function"){ //$NON-NLS-0$
  				this.explorer.scopeUp();
  			}
  		}
docs: Left arrow key collapses the current row. If current row is not expandable(e.g. a file in file navigator), move the cursor to its parent row. If current row is expandable and expanded, collapse it. Otherwise move the cursor to its parent row.