Show reset to default button for theming values on hover, fix #3198

Signed-off-by: Jan-Christoph Borchardt <hey@jancborchardt.net>

apps/theming/css/settings-admin.css

@@ -42,6 +42,8 @@ form.uploadButton {
     right: 0px;
     visibility: visible;
 }
+#theming input[type='text']:hover + .theme-undo,
+#theming input[type='text'] + .theme-undo:hover,
 #theming input[type='text']:focus + .theme-undo,
 #theming input[type='text']:active + .theme-undo {
     visibility: visible;