Fixed nested overlay - path animation can't be seen between the transition from previous overlay to current.

Added relativeToWindow(boolean) property to MaterialOverlay.

Author: kevzlou7979

src/main/java/gwt/material/design/addins/client/overlay/MaterialOverlay.java

@@ -174,6 +174,14 @@ public void setExtraTransitionDuration(int extraTransitionDuration) {
         animator.setExtraTransitionDuration(extraTransitionDuration);
     }
 
+    public void setRelativeToWindow(boolean relativeToWindow) {
+        animator.setRelativeToWindow(relativeToWindow);
+    }
+
+    public boolean isRelativeToWindow() {
+        return animator.isRelativeToWindow();
+    }
+
     @Override
     public HandlerRegistration addCloseHandler(CloseHandler<MaterialOverlay> closeHandler) {
         return addHandler(new CloseHandler<MaterialOverlay>() {

src/main/resources/gwt/material/design/addins/client/overlay/resources/css/overlay.css

@@ -6,7 +6,7 @@
     right: 0;
     bottom: 0;
     position: fixed;
-    z-index: 1000;
+    z-index: 999;
     visibility: hidden;
     opacity: 0;
 }

src/main/resources/gwt/material/design/addins/client/overlay/resources/css/overlay.min.css

@@ -130,7 +130,5 @@ public void testNestedOverlay() {
         child.addCloseHandler(closeEvent -> assertEquals("hidden", RootPanel.get().getElement().getStyle().getOverflow()));
         assertEquals(RootPanel.get(), overlay.getParent());
         assertEquals(overlay, child.getParent());
-
-
     }
 }