diff --git a/Frame.C b/Frame.C
index 0388708..d20104c 100644
--- a/Frame.C
+++ b/Frame.C
@@ -1,5 +1,6 @@
 // Frame.C
 
+#define FL_INTERNALS 1
 #include "config.h"
 #include "Frame.H"
 #include "Desktop.H"
@@ -915,7 +916,7 @@ void Frame::raise() {
   // preserving stacking order:
   for (p = &first; *p;) {
     Frame* f = *p;
-    if (f == this || f->is_transient_for(this) && f->state() != UNMAPPED) {
+    if (f == this || (f->is_transient_for(this) && f->state() != UNMAPPED)) {
       *p = f->next; // remove it from list
       if (previous) {
 	XWindowChanges w;
@@ -970,7 +971,7 @@ void Frame::lower() {
 
 void Frame::iconize() {
   for (Frame* c = first; c; c = c->next) {
-    if (c == this || c->is_transient_for(this) && c->state() != UNMAPPED)
+    if (c == this || (c->is_transient_for(this) && c->state() != UNMAPPED))
       c->state(ICONIC);
   }
 }
@@ -1163,7 +1164,7 @@ void Frame::show_hide_buttons() {
 #endif
   }
   if (min_h == max_h || flag(KEEP_ASPECT|NO_RESIZE) ||
-      !max_h_button.value() && by+label_w+2*BUTTON_H > h()-BUTTON_BOTTOM) {
+      (!max_h_button.value() && by+label_w+2*BUTTON_H > h()-BUTTON_BOTTOM)) {
     max_h_button.hide();
   } else {
     max_h_button.position(BUTTON_LEFT,by);
@@ -1171,7 +1172,7 @@ void Frame::show_hide_buttons() {
     by += BUTTON_H;
   }
   if (min_w == max_w || flag(KEEP_ASPECT|NO_RESIZE) ||
-      !max_w_button.value() && by+label_w+2*BUTTON_H > h()-BUTTON_BOTTOM) {
+      (!max_w_button.value() && by+label_w+2*BUTTON_H > h()-BUTTON_BOTTOM)) {
     max_w_button.hide();
   } else {
     max_w_button.position(BUTTON_LEFT,by);
@@ -1646,8 +1647,8 @@ int Frame::handle(int e) {
 	nh = iy+ih-(Fl::event_y_root()-dy);
       else {ny = y(); nh = h();}
       if (flag(KEEP_ASPECT)) {
-	if (nw-dwidth > nh-dwidth
-	    && (what&(FL_ALIGN_LEFT|FL_ALIGN_RIGHT))
+	if ((nw-dwidth > nh-dwidth
+             && (what&(FL_ALIGN_LEFT|FL_ALIGN_RIGHT)))
 	    || !(what&(FL_ALIGN_TOP|FL_ALIGN_BOTTOM)))
 	  nh = nw-dwidth+dheight;
 	else
diff --git a/Hotkeys.C b/Hotkeys.C
index df80930..059ee2d 100644
--- a/Hotkeys.C
+++ b/Hotkeys.C
@@ -182,8 +182,8 @@ int test_shortcut(int shortcut) {
 int Handle_Hotkey() {
   for (int i = 0; keybindings[i].key; i++) {
     if (Fl::test_shortcut(keybindings[i].key) ||
-	(keybindings[i].key & 0xFFFF) == FL_Delete
-	&& Fl::event_key() == FL_BackSpace// fltk bug?
+	((keybindings[i].key & 0xFFFF) == FL_Delete
+         && Fl::event_key() == FL_BackSpace)// fltk bug?
 	) {
       keybindings[i].func();
       return 1;
diff --git a/Menu.C b/Menu.C
index 0f6e8cf..8572f1d 100644
--- a/Menu.C
+++ b/Menu.C
@@ -568,7 +568,7 @@ ShowTabMenu(int tab)
       if (d == Desktop::current()) first_on_desk = menu+n;
       for (c = Frame::first; c; c = c->next) {
 	if (c->state() == UNMAPPED || c->transient_for()) continue;
-	if (c->desktop() == d || !c->desktop() && d == Desktop::current()) {
+	if (c->desktop() == d || (!c->desktop() && d == Desktop::current())) {
 	  init(menu[n],(char*)c);
 #if FL_MAJOR_VERSION < 2
 	  init(menu[n],(char*)c);
diff --git a/Rotated.C b/Rotated.C
index cf382fb..ae30ea3 100644
--- a/Rotated.C
+++ b/Rotated.C
@@ -26,6 +26,7 @@
 
 /* ********************************************************************** */
 
+#define FL_INTERNALS 1
 #include <FL/x.H>
 #if FL_MAJOR_VERSION < 2
 # define XWindow Window
diff --git a/main.C b/main.C
index c8ac8ec..b03d21a 100644
--- a/main.C
+++ b/main.C
@@ -2,6 +2,7 @@
 // you can test the window controls.
 //#define TEST 1
 
+#define FL_INTERNALS 1
 #include "Frame.H"
 #include <X11/Xproto.h>
 #include <stdio.h>