diff --git a/nx-X11/programs/Xserver/hw/nxagent/Drawable.c b/nx-X11/programs/Xserver/hw/nxagent/Drawable.c
index 2b81a55f5463f0ae1783235737a389e7fcd0e1ce..ca1b09dd32304ea8add86384f3c9e00277088489 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/Drawable.c
+++ b/nx-X11/programs/Xserver/hw/nxagent/Drawable.c
@@ -2309,7 +2309,7 @@ void nxagentCorruptedRegionOnWindow(void *p0, XID x, void *p2)
    * The window is not visible.
    */
 
-  if (nxagentWindowIsVisible(pWin) == 0)
+  if (!nxagentWindowIsVisible(pWin))
   {
     return;
   }
diff --git a/nx-X11/programs/Xserver/hw/nxagent/GCOps.c b/nx-X11/programs/Xserver/hw/nxagent/GCOps.c
index ee56e9abf38b46ffad34e4d625671a3c1394b913..57b7c2b5762d9578f8833960f022e309e7a21c1d 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/GCOps.c
+++ b/nx-X11/programs/Xserver/hw/nxagent/GCOps.c
@@ -699,8 +699,8 @@ RegionPtr nxagentCopyArea(DrawablePtr pSrcDrawable, DrawablePtr pDstDrawable,
    */
 
   if (!nxagentOption(IgnoreVisibility) && pDstDrawable -> type == DRAWABLE_WINDOW &&
-          (nxagentWindowIsVisible((WindowPtr) pDstDrawable) == 0 ||
-              (nxagentDefaultWindowIsVisible() == 0 && nxagentCompositeEnable == 0)))
+          (!nxagentWindowIsVisible((WindowPtr) pDstDrawable) ||
+              (!nxagentDefaultWindowIsVisible() && nxagentCompositeEnable == 0)))
   {
     #ifdef TEST
     fprintf(stderr, "nxagentCopyArea: Prevented operation on fully obscured window at [%p].\n",
diff --git a/nx-X11/programs/Xserver/hw/nxagent/Image.c b/nx-X11/programs/Xserver/hw/nxagent/Image.c
index eb4085ef347228ae07749230d965cf17e5eb2818..8c828df20309fa8901a96690789d9574b8fa6805 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/Image.c
+++ b/nx-X11/programs/Xserver/hw/nxagent/Image.c
@@ -525,8 +525,8 @@ void nxagentPutImage(DrawablePtr pDrawable, GCPtr pGC, int depth,
    */
 
   if (!nxagentOption(IgnoreVisibility) && pDrawable -> type == DRAWABLE_WINDOW &&
-          (nxagentWindowIsVisible((WindowPtr) pDrawable) == 0 ||
-              (nxagentDefaultWindowIsVisible() == 0 && nxagentCompositeEnable == 0)))
+          (!nxagentWindowIsVisible((WindowPtr) pDrawable) ||
+              (!nxagentDefaultWindowIsVisible() && nxagentCompositeEnable == 0)))
   {
 
     #ifdef TEST
diff --git a/nx-X11/programs/Xserver/hw/nxagent/Pixels.h b/nx-X11/programs/Xserver/hw/nxagent/Pixels.h
index 7426acab23d232d23f40141e0aaf6812287f5749..cf5e50c04f18edf5d1e1f0d2f9ff49f8715f97d4 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/Pixels.h
+++ b/nx-X11/programs/Xserver/hw/nxagent/Pixels.h
@@ -173,8 +173,8 @@ FIXME: Changed macro: NXAGENT_SHOULD_DEFER_COMPOSITE
  */
 
 #define NXAGENT_SHOULD_SYNCHRONIZE_WINDOW(pDrawable)  \
-    (nxagentWindowIsVisible((WindowPtr) pDrawable) == 1 && \
-        (nxagentDefaultWindowIsVisible() == 1 || nxagentCompositeEnable == 1))
+    (nxagentWindowIsVisible((WindowPtr) pDrawable) && \
+        (nxagentDefaultWindowIsVisible() || nxagentCompositeEnable == 1))
 
 #define MINIMUM_PIXMAP_USAGE_COUNTER 2