public override void OnClick() { //The snap editor form requires an edit session (e.g. in order to read the target layer and to set the snap tips) IEngineEditor editor = new EngineEditorClass(); if (editor.EditState != esriEngineEditState.esriEngineStateEditing) { System.Windows.Forms.MessageBox.Show("Please start an edit session"); return; } //Show the snap settings form if (snapEditor == null || snapEditor.IsDisposed) { snapEditor = new SnapEditor(); } snapEditor.Show(); snapEditor.BringToFront(); }