Dont' scroll the slider if the futureSliderView is hidden.

Clocker/Panel/PanelController.swift

@@ -363,9 +363,14 @@ class PanelController: ParentPanelController {
             Logger.log(object: nil, for: "Scroll Event Ended")
         }
 
+        // We only want to move the slider if the slider is visible.
+        // If the parent view is hidden, then that doesn't automatically mean that all the childViews are also hidden
+        // Hence, check if the parent view is totally hidden or not..
+        if futureSliderView.isHidden == false {
             futureSlider.doubleValue += Double(event.scrollingDeltaX)
             sliderMoved(futureSlider!)
         }
+    }
 }
 
 extension PanelController: NSWindowDelegate {