themes: Issue #4095. Add a on-hover effect to the menu-item …

… radio buttons to improve their readability against dark backgrounds.

Dark theme only.

themes/Dark/Makefile.am

@@ -107,8 +107,11 @@ themeui_DATA =	\
 	ui/notebook.png	\
 	ui/null.png	\
 	ui/option1.png	\
+	ui/option1-prelight.png	\
 	ui/option2.png	\
+	ui/option2-prelight.png	\
 	ui/option3.png	\
+	ui/option3-prelight.png	\
 	ui/plus.png	\
 	ui/progressbar.png	\
 	ui/progressbar-trough.png	\

themes/Dark/gtkrc

@@ -781,6 +781,36 @@ style "gimp-dark-menu-item"
           stretch = TRUE
         }
 
+      image
+        {
+          function = OPTION
+          state = PRELIGHT
+          shadow = OUT
+          recolorable = TRUE
+          overlay_file = "ui/option1-prelight.png"
+          overlay_stretch = FALSE
+        }
+
+      image
+        {
+          function = OPTION
+          state = PRELIGHT
+          shadow = IN
+          recolorable = TRUE
+          overlay_file = "ui/option2-prelight.png"
+          overlay_stretch = FALSE
+        }
+        
+      image
+        {
+          function = OPTION
+          state = PRELIGHT
+          shadow = ETCHED_IN
+          recolorable = TRUE
+          overlay_file = "ui/option3-prelight.png"
+          overlay_stretch = FALSE
+        }
+
       image
         {
           function = OPTION