diff --git a/src/screen_xywh.cxx b/src/screen_xywh.cxx
index 6becbf979..9ed788d0b 100644
--- a/src/screen_xywh.cxx
+++ b/src/screen_xywh.cxx
@@ -56,7 +56,7 @@ typedef BOOL (WINAPI* fl_gmi_func)(HMONITOR, LPMONITORINFO);
 static fl_gmi_func fl_gmi = NULL; // used to get a proc pointer for GetMonitorInfoA
 
 static RECT screens[16];
-static int dpi[16][2] = { { 0.0f, 0.0f } };
+static float dpi[16][2];
 
 static BOOL CALLBACK screen_cb(HMONITOR mon, HDC, LPRECT r, LPARAM) {
   if (num_screens >= 16) return TRUE;
@@ -135,14 +135,19 @@ static void screen_init() {
 
   if (XineramaIsActive(fl_display)) {
     screens = XineramaQueryScreens(fl_display, &num_screens);
-  } else num_screens = 1;
-
-  int i;
-  for (i=0; i<num_screens; i++) {
-    int mm = DisplayWidthMM(fl_display, i);
-    dpi[i][0] = mm ? screens[i].width*25.4f/mm : 0.0f;
+    int i;
+    for (i=0; i<num_screens; i++) {
+      int mm = DisplayWidthMM(fl_display, i);
+      dpi[i][0] = mm ? screens[i].width*25.4f/mm : 0.0f;
+      mm = DisplayHeightMM(fl_display, fl_screen);
+      dpi[i][1] = mm ? screens[i].height*25.4f/mm : dpi[i][0];
+    }
+  } else { // ! XineramaIsActive()
+    num_screens = 1;
+    int mm = DisplayWidthMM(fl_display, fl_screen);
+    dpi[0][0] = mm ? Fl::w()*25.4f/mm : 0.0f;
     mm = DisplayHeightMM(fl_display, fl_screen);
-    dpi[i][1] = mm ? screens[i].height*25.4f/mm : dpi[i][0];  
+    dpi[0][1] = mm ? Fl::h()*25.4f/mm : dpi[0][0];
   }
 }
 #else
diff --git a/test/hello.cxx b/test/hello.cxx
index e4372e49a..d0daff93f 100644
--- a/test/hello.cxx
+++ b/test/hello.cxx
@@ -30,9 +30,17 @@
 #include <FL/Fl_Box.H>
 
 int main(int argc, char **argv) {
-  float h, v;
-  Fl::screen_dpi(h, v);
-  printf("Screen res is %g x %g ppi\n", h, v);
+#if (1) // FIXME: test screen dimensions and resolution. Remove before release !
+  float ppi_h, ppi_v;
+  int x,y,w,h;
+  int n = Fl::screen_count();
+  for (int i=0; i<n; i++) {
+    Fl::screen_xywh(x,y,w,h,i);
+    Fl::screen_dpi(ppi_h, ppi_v, i);
+    printf("Screen %2d (%4d,%4d,%4d,%4d) res. is %7.3f x %7.3f ppi\n", i, x,y,w,h, ppi_h, ppi_v);
+  }
+  fflush(stdout);
+#endif // FIXME: test screen dimensions and resolution. Remove before release !
   Fl_Window *window = new Fl_Window(340,180);
   Fl_Box *box = new Fl_Box(20,40,300,100,"Hello, World!");
   box->box(FL_UP_BOX);