fix: double click event handling (#232)

add comment to not forget `event.detail` on `pointerup` / `pointerdown` do not have clickCount information

Refs: Actelion/openchemlib#114
Closes: #225

lib/canvas_editor/events.js

@@ -30,14 +30,14 @@ function addPointerListeners(canvasElement, drawArea, JavaEditorArea) {
   canvasElement.addEventListener('pointerdown', (ev) => {
     if (pointerDownId === -1) {
       pointerDownId = ev.pointerId;
-      fireMouseEvent(JavaEditorArea.MOUSE_EVENT_PRESSED, ev, ev.detail);
+      fireMouseEvent(JavaEditorArea.MOUSE_EVENT_PRESSED, ev);
     }
   });
 
   function handlePointerUp(ev) {
     if (pointerDownId === ev.pointerId) {
       pointerDownId = -1;
-      fireMouseEvent(JavaEditorArea.MOUSE_EVENT_RELEASED, ev, ev.detail);
+      fireMouseEvent(JavaEditorArea.MOUSE_EVENT_RELEASED, ev);
     }
   }
   // Listen on document to capture mouse release outside the canvas.
@@ -47,9 +47,11 @@ function addPointerListeners(canvasElement, drawArea, JavaEditorArea) {
     fireMouseEvent(JavaEditorArea.MOUSE_EVENT_CLICKED, ev, ev.detail);
   });
   canvasElement.addEventListener('pointerenter', (ev) => {
+    // event.detail on pointerenter doesn't include the click count
     fireMouseEvent(JavaEditorArea.MOUSE_EVENT_ENTERED, ev);
   });
   canvasElement.addEventListener('pointerleave', (ev) => {
+    // event.detail on pointerenter doesn't include the click count
     fireMouseEvent(JavaEditorArea.MOUSE_EVENT_EXITED, ev);
   });
   canvasElement.addEventListener('pointermove', (ev) => {