Fixed 'for' attribute value on label

Author: Jaume Ribas

image-sequence-viewer.html

@@ -73,7 +73,7 @@
 				</label>
 				<input type="number" id="index-leap" name="index-leap" value="1" title="The index increment between consecutive images">
 
-				<label for="index-leap">
+				<label for="filp-upside-down">
 				<span>Flip upside down: </span>
 				</label>
 				<input type="checkbox" id="filp-upside-down" name="filp-upside-down" title="Inverts the images vertically">