Namely: 1. In caja_is_drawing..(), only get atom for WM_CLASS property if it exists. 2. Cache gsettings draw-background & show-desktop-icons key-values, and only update when either actually changes, to avoid unnecessary queries to the dconf-service. 3. Avoid conflicts between settings_change_event_cb() & on_bg_handling_changed(). 4. Keep track of screen sizes, to ensure size actually changed when signalled, to avoid double-redraw on an extraneous signal, which can lockup the daemon, because we draw immediately (w/out g_idle_add). Though we don't fade in re-draws triggered by size/monitors-changed signals, making all re-draws queued causes issues with fading, when we do fade (on bg change), and queueing is unnecessary here anyway. 5. Track a redraw in progress, to avoid any possible (and unforseeable) clashes.