diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
index 2a09ca7b6a84..942c01c0a08b 100644
--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -124,7 +124,7 @@ extern "C" {
 // defined in nsMenuBarX.mm
 extern NSMenu* sApplicationMenu; // Application menu shared by all menubars
 
-bool gChildViewMethodsSwizzled = false;
+static bool gChildViewMethodsSwizzled = false;
 
 extern nsISupportsArray *gDraggedTransferables;
 
@@ -4752,7 +4752,6 @@ NSEvent* gLastDragMouseDownEvent = nil;
   mUsingOMTCompositor = aUseOMTC;
 }
 
-
 // Returning NO from this method only disallows ordering on mousedown - in order
 // to prevent it for mouseup too, we need to call [NSApp preventWindowOrdering]
 // when handling the mousedown event.
@@ -5544,14 +5543,18 @@ static int32_t RoundUp(double aDouble)
     case NSOtherMouseDragged:
       if ([aMouseEvent subtype] == NSTabletPointEventSubtype) {
         mouseEvent->pressure = [aMouseEvent pressure];
+        MOZ_ASSERT(mouseEvent->pressure >= 0.0 && mouseEvent->pressure <= 1.0);
       }
       break;
+
+    default:
+      // Don't check other NSEvents for pressure.
+      break;
   }
 
   NS_OBJC_END_TRY_ABORT_BLOCK;
 }
 
-
 #pragma mark -
 // NSTextInput implementation