X11: Fix EWMH state update for hidden windows

The EWMH window state code assumed the window was mapped.

Fixes #1358.

README.md

@@ -250,6 +250,8 @@ information on what to include when reporting a bug.
 - [X11] Bugfix: `glfwSetWindowMonitor` did not update hints when resizing
                 non-user-resizable windows
 - [X11] Bugfix: `glfwSetWindowMonitor` did not flush output buffer in some cases
+- [X11] Bugfix: `glfwSetWindowMonitor` did not update the EWMH state of hidden
+                windows (#1358)
 - [Linux] Added workaround for missing `SYN_DROPPED` in pre-2.6.39 kernel
           headers (#1196)
 - [Linux] Moved to evdev for joystick input (#906,#1005)

src/x11_window.c

@@ -2410,16 +2410,21 @@ void _glfwPlatformSetWindowMonitor(_GLFWwindow* window,
 
     _glfwInputWindowMonitor(window, monitor);
     updateNormalHints(window, width, height);
-    updateWindowMode(window);
 
     if (window->monitor)
     {
-        XMapRaised(_glfw.x11.display, window->x11.handle);
-        if (waitForVisibilityNotify(window))
-            acquireMonitor(window);
+        if (!_glfwPlatformWindowVisible(window))
+        {
+            XMapRaised(_glfw.x11.display, window->x11.handle);
+            waitForVisibilityNotify(window);
+        }
+
+        updateWindowMode(window);
+        acquireMonitor(window);
     }
     else
     {
+        updateWindowMode(window);
         XMoveResizeWindow(_glfw.x11.display, window->x11.handle,
                           xpos, ypos, width, height);
     }