APIDiagram Editor APIHistory manager APIHistory manager methodsisUndo()On this pageisUndo() Description Checks whether an action has been revertedUsageisUndo(): boolean;Exampleconst editor = new dhx.DiagramEditor("editor_container", { type: "default"});// ...editor.history.isUndo();ReturnsThe method returns true, if an action has been reverted; otherwise, falseChange log: Added in v4.1