added a note about "save page in background"

extension/ui/pages/help.html

@@ -314,7 +314,8 @@
 					<li data-options-label="backgroundSaveLabel"> <span class="option">Option: save pages in
 							background</span>
 						<p>Uncheck this option if you get invalid file names like
-							"37bec68b-446a-46a5-8642-19a89c231b46.html" or interrupted downloads when saving pages.
+							"37bec68b-446a-46a5-8642-19a89c231b46.html" or interrupted downloads when saving pages. You
+							can also check this option if you want the "Save as" dialog to remember the last saved path.
 							Unchecking this option prevent using sub-directories in filename templates.</p>
 						<p class="notice">It is recommended to <u>check</u> this option</p>
 					</li>