Don't delete undeletable blocks dragged onto a delete area (issue 52).

blockly_compressed.js

@@ -1032,8 +1032,8 @@ Blockly.BlockSvg.prototype.getHeightWidth=function(){var a=this.height,b=this.wi
 Blockly.BlockSvg.prototype.setCollapsed=function(a){if(this.collapsed_!=a){Blockly.BlockSvg.superClass_.setCollapsed.call(this,a);for(var b=[],c=0,d;d=this.inputList[c];c++)b.push.apply(b,d.setVisible(!a));if(a){a=this.getIcons();for(c=0;c<a.length;c++)a[c].setVisible(!1);c=this.toString(Blockly.COLLAPSE_CHARS);this.appendDummyInput("_TEMP_COLLAPSED_INPUT").appendField(c).init()}else this.removeInput("_TEMP_COLLAPSED_INPUT");b.length||(b[0]=this);if(this.rendered){for(c=0;a=b[c];c++)a.render();this.bumpNeighbours_()}}};
 Blockly.BlockSvg.prototype.onMouseDown_=function(a){if(!this.isInFlyout){Blockly.svgResize();Blockly.terminateDrag_();this.select();Blockly.hideChaff();if(Blockly.isRightButton(a))this.showContextMenu_(a);else if(this.isMovable()){Blockly.removeAllRanges();Blockly.Css.setCursor(Blockly.Css.Cursor.CLOSED);var b=this.getRelativeToSurfaceXY();this.startDragX=b.x;this.startDragY=b.y;this.startDragMouseX=a.clientX;this.startDragMouseY=a.clientY;Blockly.dragMode_=1;Blockly.BlockSvg.onMouseUpWrapper_=Blockly.bindEvent_(document,
 "mouseup",this,this.onMouseUp_);Blockly.BlockSvg.onMouseMoveWrapper_=Blockly.bindEvent_(document,"mousemove",this,this.onMouseMove_);this.draggedBubbles_=[];for(var b=this.getDescendants(),c=0,d;d=b[c];c++){d=d.getIcons();for(var e=0;e<d.length;e++){var f=d[e].getIconLocation();f.bubble=d[e];this.draggedBubbles_.push(f)}}}else return;a.stopPropagation()}};
-Blockly.BlockSvg.prototype.onMouseUp_=function(a){var b=this;Blockly.doCommand(function(){Blockly.terminateDrag_();if(Blockly.selected&&Blockly.highlightedConnection_)Blockly.localConnection_.connect(Blockly.highlightedConnection_),b.rendered&&(Blockly.localConnection_.isSuperior()?Blockly.highlightedConnection_:Blockly.localConnection_).sourceBlock_.connectionUiEffect(),b.workspace.trashcan&&b.workspace.trashcan.close();else if(b.workspace.isDeleteArea(a)){var c=b.workspace.trashcan;c&&goog.Timer.callOnce(c.close,
-100,c);Blockly.selected.dispose(!1,!0);Blockly.fireUiEvent(window,"resize")}Blockly.highlightedConnection_&&(Blockly.highlightedConnection_.unhighlight(),Blockly.highlightedConnection_=null);Blockly.Css.setCursor(Blockly.Css.Cursor.OPEN)})};Blockly.BlockSvg.prototype.showHelp_=function(){var a=goog.isFunction(this.helpUrl)?this.helpUrl():this.helpUrl;a&&window.open(a)};
+Blockly.BlockSvg.prototype.onMouseUp_=function(a){var b=this;Blockly.doCommand(function(){Blockly.terminateDrag_();if(Blockly.selected&&Blockly.highlightedConnection_)Blockly.localConnection_.connect(Blockly.highlightedConnection_),b.rendered&&(Blockly.localConnection_.isSuperior()?Blockly.highlightedConnection_:Blockly.localConnection_).sourceBlock_.connectionUiEffect(),b.workspace.trashcan&&b.workspace.trashcan.close();else if(b.workspace.isDeleteArea(a)&&Blockly.selected.isDeletable()){var c=b.workspace.trashcan;
+c&&goog.Timer.callOnce(c.close,100,c);Blockly.selected.dispose(!1,!0);Blockly.fireUiEvent(window,"resize")}Blockly.highlightedConnection_&&(Blockly.highlightedConnection_.unhighlight(),Blockly.highlightedConnection_=null);Blockly.Css.setCursor(Blockly.Css.Cursor.OPEN)})};Blockly.BlockSvg.prototype.showHelp_=function(){var a=goog.isFunction(this.helpUrl)?this.helpUrl():this.helpUrl;a&&window.open(a)};
 Blockly.BlockSvg.prototype.showContextMenu_=function(a){if(!Blockly.readOnly&&this.contextMenu){var b=this,c=[];if(this.isDeletable()&&this.isMovable()&&!b.isInFlyout){var d={text:Blockly.Msg.DUPLICATE_BLOCK,enabled:!0,callback:function(){b.duplicate_()}};this.getDescendants().length>this.workspace.remainingCapacity()&&(d.enabled=!1);c.push(d);this.isEditable()&&!this.collapsed_&&Blockly.comments&&(d={enabled:!0},this.comment?(d.text=Blockly.Msg.REMOVE_COMMENT,d.callback=function(){b.setCommentText(null)}):
 (d.text=Blockly.Msg.ADD_COMMENT,d.callback=function(){b.setCommentText("")}),c.push(d));if(!this.collapsed_)for(d=0;d<this.inputList.length;d++)if(this.inputList[d].type==Blockly.INPUT_VALUE){d={enabled:!0};d.text=this.inputsInline?Blockly.Msg.EXTERNAL_INPUTS:Blockly.Msg.INLINE_INPUTS;d.callback=function(){b.setInputsInline(!b.inputsInline)};c.push(d);break}Blockly.collapse&&(this.collapsed_?(d={enabled:!0},d.text=Blockly.Msg.EXPAND_BLOCK,d.callback=function(){b.setCollapsed(!1)}):(d={enabled:!0},
 d.text=Blockly.Msg.COLLAPSE_BLOCK,d.callback=function(){b.setCollapsed(!0)}),c.push(d));Blockly.disable&&(d={text:this.disabled?Blockly.Msg.ENABLE_BLOCK:Blockly.Msg.DISABLE_BLOCK,enabled:!this.getInheritedDisabled(),callback:function(){b.setDisabled(!b.disabled)}},c.push(d));var d=this.getDescendants().length,e=this.getNextBlock();e&&(d-=e.getDescendants().length);d={text:1==d?Blockly.Msg.DELETE_BLOCK:Blockly.Msg.DELETE_X_BLOCKS.replace("%1",String(d)),enabled:!0,callback:function(){b.dispose(!0,

core/block_svg.js

@@ -405,7 +405,8 @@ Blockly.BlockSvg.prototype.onMouseUp_ = function(e) {
         // Don't throw an object in the trash can if it just got connected.
         this_.workspace.trashcan.close();
       }
-    } else if (this_.workspace.isDeleteArea(e)) {
+    } else if (this_.workspace.isDeleteArea(e) &&
+        Blockly.selected.isDeletable()) {
       var trashcan = this_.workspace.trashcan;
       if (trashcan) {
         goog.Timer.callOnce(trashcan.close, 100, trashcan);