added 1730411 to disco known bugs

posts/release/disco/final/post.md

@@ -13,6 +13,7 @@ Desktop Environment
  * lxqt-session allocates memory for process output never read ([1823416](https://bugs.launchpad.net/ubuntu/+source/lxqt-session/+bug/1823416))
  * using BROWSER environment variable to set default browser creates several problems; workaround available ([182654](https://bugs.launchpad.net/ubuntu/+source/lxqt-session/+bug/1824654))
  * LXQt Arc theme + Breeze widgets hides menu scroll bar when searching ([1787734](https://bugs.launchpad.net/ubuntu/+source/lubuntu-artwork/+bug/1787734))
+ * Multiple monitors wallpaper handled as only one big monitor ([1730411](https://bugs.launchpad.net/lxqt/+bug/1730411))
 
 Applications
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