all changes reverted, bugs should be gone

src/containers/stage.jsx

@@ -179,16 +179,15 @@ class Stage extends React.Component {
         this.updateRect();
         const {x, y} = getEventXY(e);
         const mousePosition = [x - this.rect.left, y - this.rect.top];
-        if (true) {
-            this.setState({
-                mouseDown: true,
-                mouseDownPosition: mousePosition,
-                mouseDownTimeoutId: setTimeout(
-                    this.onStartDrag.bind(this, mousePosition[0], mousePosition[1]),
-                    500
-                )
-            });
-        }
+        this.setState({
+            mouseDown: true,
+            mouseDownPosition: mousePosition,
+            mouseDownTimeoutId: setTimeout(
+                this.onStartDrag.bind(this, mousePosition[0], mousePosition[1]),
+                500
+            )
+        });
+
         const data = {
             isDown: true,
             x: mousePosition[0],