limit asset editor undo to current session

Author: fredsa

src/ide/views/asseteditor.ts

@@ -381,6 +381,8 @@ export class AssetEditorView implements ProjectView, pixed.EditorContext {
   setVisible?(showing: boolean): void {
     // TODO: make into toolbar?
     if (showing) {
+      // limit undo to since opening this editor
+      projectWindows.undofiles = [];
       if (Mousetrap.bind) Mousetrap.bind('mod+z', projectWindows.undoStep.bind(projectWindows));
     } else {
       if (Mousetrap.unbind) Mousetrap.unbind('mod+z');