diff --git a/api/js/etemplate/Expose/ExposeMixin.ts b/api/js/etemplate/Expose/ExposeMixin.ts
index 10fdaf54e3..e191bc5190 100644
--- a/api/js/etemplate/Expose/ExposeMixin.ts
+++ b/api/js/etemplate/Expose/ExposeMixin.ts
@@ -921,6 +921,12 @@ export function ExposeMixin<B extends Constructor<LitElement>>(superclass : B)
 		{
 			// Check to see if we're in a nextmatch, remove magic
 			let nm = this.find_nextmatch(this);
+
+			// redefine essential removeClass method in case the active element has no longer contains it.
+			if (!this._gallery.activeIndicator.removeClass)
+			{
+				this._gallery.activeIndicator.removeClass = blueimp.helper.prototype.removeClass;
+			}
 			if(nm && !this._is_target_indepth(nm))
 			{
 				// Remove scrolling from thumbnails