act on selection

data/darktableconfig.xml.in

@@ -1650,6 +1650,13 @@
     <shortdescription>use single-click in the collections module</shortdescription>
     <longdescription>check this option to use single-click to select items in the collections module. this will allow you to do range selections for date-time and numeric values.</longdescription>
   </dtconfig>
+  <dtconfig prefs="lighttable" section="general">
+    <name>plugins/lighttable/act_on</name>
+     <type>bool</type>
+    <default>true</default>
+    <shortdescription>prioritise the hovered image over the selected images</shortdescription>
+    <longdescription>this define how the image to act on list is constructed.</longdescription>
+  </dtconfig>
   <dtconfig>
     <name>plugins/lighttable/collect/num_rules</name>
     <type min="1" max="10">int</type>

data/themes/darktable.css

@@ -657,7 +657,7 @@ dialog .sidebar row:selected:hover label,
 }
 
 .dt_section_expander {
-  padding: 0.07em 0 0.07em 1.7em;  
+  padding: 0.07em 0 0.07em 1.7em;
 }
 
 .dt_section_expander,
@@ -1915,16 +1915,24 @@ Details :
   border: 1px solid @lighttable_bg_color;
 }
 
+/* set hover effect */
+.dt_act_on_selection #thumb-main:active #thumb-back,
+.dt_act_on_selection #thumb-main:selected #thumb-back
+{
+  background-color: @thumbnail_hover_bg_color;
+}
+
 /* set selected image and/or focus one */
-#thumb-main:active #thumb-back,
-#thumb-main:selected #thumb-back
+.dt_act_on_hover #thumb-main:active #thumb-back,
+.dt_act_on_hover #thumb-main:selected #thumb-back,
+.dt_act_on_selection #thumb-main:hover #thumb-back
 {
   background-color: shade(@thumbnail_selected_bg_color, 1.05);
   border-color: shade(@thumbnail_selected_bg_color, 1.15);
 }
 
 /* set hover effect */
-#thumb-main:hover #thumb-back
+.dt_act_on_hover #thumb-main:hover #thumb-back
 {
   background-color: @thumbnail_hover_bg_color;
 }
@@ -2285,7 +2293,8 @@ Details :
   border: 0.14em solid @plugin_bg_color;
 }
 
-.dt_fullview #thumb-main:hover #thumb-image
+.dt_fullview.dt_act_on_hover #thumb-main:hover #thumb-image,
+.dt_fullview.dt_act_on_selection .dt_culling_selected#thumb-main #thumb-image
 {
   border: 0.14em solid @thumbnail_hover_bg_color;
 }