I've never really learned the rewrite tool but while waiting for changes to propagate through P12, I thought maybe I could use it to safely patch changes until there are official updates (and it was a good chance to get more familiar with it). I thought there was more documentation available for how it works (interested in any old articles - but the online help in P12 is ok - although it doesn't display in markdown - in fact give there is markdown support now - I am a bit confused what should appear more readable these days - and how to fix/contribute changes to help). This aside - I wanted to patch the SystemWindow>>taskbarButtonMenu: (and add my fix to move tabs to any position). I started writing the following search expression - the find the last call to #addToggle:... method call that has a literal referencing #canBeMovedRight - as I want to add my new menu item after it. e.g. moveSubmenu `@addToggle: `{ :node | node isLiteralNode and: [ node value = #canBeMovedToRight] } but I'm not sure my {} filter block is ever called, as the above matches both addToggle:... calls, and not the one I'm after? I don't understand this - any have ideas on the proper syntax for generic matching? Anyway - I decided that in my case there is only one - so I can match it explicitly and so I search on the full call: and I entered this: moveSubmenu addToggle: 'Move right' translated target: self selector: #taskbarMoveRight getStateSelector: nil enablementSelector: #canBeMovedToRight. Which matches exactly - then I want to replace the single statement with 2 statements e.g. moveSubmenu addToggle: 'Move right' translated target: self selector: #taskbarMoveRight getStateSelector: nil enablementSelector: #canBeMovedToRight. moveSubmenu addToggle: 'Move to' translated target: self selector: #taskbarMoveTo getStateSelector: nil. However this gives an error in the rewrite tool (actually it results in a zero change, that then gives an error for EpMonitor). But my question is - why can't you rewrite a single statement to multiple ones? I have noticed that in this case I can cascade the message send - and this then rewrites properly - so it looks like it wants to replace a single node with a single node. If I couldn't cascade - It seems I would have to rewrite with something like: [ "put multiple expressions here" ] value. This seems an odd choice - but am I missing something obvious? Do you have to do what I'm proposing in 2 steps - rewrite to a block (or some equivalent) and then a 2nd rewrite to simplify the expression (like a refactor step) - so its more provably correct? I'm just curious on this - as it seemed time to learn this properly? Tim