diff --git a/resource/modules/UI.jsm b/resource/modules/UI.jsm
index c9e008c..e1e3f1c 100644
--- a/resource/modules/UI.jsm
+++ b/resource/modules/UI.jsm
@@ -780,6 +780,15 @@ this.UI = {
 
 	useDarkTheme: function() {
 		toggleAttribute(document.body, 'darktheme', brightText.useDarkTheme());
+
+		// Refresh group thumb
+		if(this.single) {
+			this._resize(true);
+			for(let groupItem of GroupItems) {
+				groupItem.setTitle(groupItem.getTitle());
+				groupItem.updateThumb(true);
+			}
+		}
 	},
 
 	goToPreferences: function(aOptions) {