diff -up xfce4-settings-4.12.0/xfsettingsd/displays.c.z-xfce4-settings-multimonitor-reconnect-fix xfce4-settings-4.12.0/xfsettingsd/displays.c
--- xfce4-settings-4.12.0/xfsettingsd/displays.c.z-xfce4-settings-multimonitor-reconnect-fix	2015-02-24 04:33:11.000000000 +0300
+++ xfce4-settings-4.12.0/xfsettingsd/displays.c	2017-05-25 16:39:43.843704777 +0300
@@ -499,6 +499,10 @@ xfce_displays_helper_screen_on_event (Gd
                     changed = TRUE;
                 }
             }
+
+            if (changed)
+                xfce_displays_helper_channel_apply (helper, DEFAULT_SCHEME_NAME);
+
             /* Start the minimal dialog according to the user preferences */
             if (changed && xfconf_channel_get_bool (helper->channel, NOTIFY_PROP, FALSE))
                 xfce_spawn_command_line_on_screen (NULL, "xfce4-display-settings -m", FALSE,
@@ -539,10 +543,10 @@ xfce_displays_helper_set_screen_size (Xf
     /* set the screen size only if it's really needed and valid */
     if (helper->width >= min_width && helper->width <= max_width
         && helper->height >= min_height && helper->height <= max_height
-        && (helper->width != gdk_screen_width ()
+        /*&& (helper->width != gdk_screen_width ()
             || helper->height != gdk_screen_height ()
             || helper->mm_width != gdk_screen_width_mm ()
-            || helper->mm_height != gdk_screen_height_mm ()))
+            || helper->mm_height != gdk_screen_height_mm ())*/)
     {
         xfsettings_dbg (XFSD_DEBUG_DISPLAYS, "Applying desktop dimensions: %dx%d (px), %dx%d (mm).",
                         helper->width, helper->height, helper->mm_width, helper->mm_height);