diff --git a/src/mission.c b/src/mission.c
index 04c5e94..6868812 100644
--- a/src/mission.c
+++ b/src/mission.c
@@ -334,6 +334,7 @@ static void mission_freeData(MissionData* mission) {
   if(mission->avail.planet)   free(mission->avail.planet);
   if(mission->avail.system)   free(mission->avail.system);
   if(mission->avail.factions) free(mission->avail.factions);
+  if(mission->avail.cond)     free(mission->avail.cond);
   memset(mission, 0, sizeof(MissionData));
 }
 
diff --git a/src/opengl.c b/src/opengl.c
index f7bfda3..455b5a6 100644
--- a/src/opengl.c
+++ b/src/opengl.c
@@ -459,7 +459,8 @@ void gl_freeTexture(glTexture* texture) {
       if(cur->used <= 0) {
         /* Not used anymore - Free the texture. */
         glDeleteTextures(1, &texture->texture);
-        if(texture->trans) free(texture->trans);
+        if(texture->trans != NULL) free(texture->trans);
+        if(texture->name != NULL)  free(texture->name);
         free(texture);
 
         /* Free the list node. */
diff --git a/src/spfx.c b/src/spfx.c
index 5dcb05f..7389abc 100644
--- a/src/spfx.c
+++ b/src/spfx.c
@@ -72,8 +72,8 @@ static int spfx_base_load(char* name, int anim, char* gfx, int sx, int sy) {
 }
 
 static void spfx_base_free(SPFX_Base* effect) {
-  if(effect->name) free(effect->name);
-  if(effect->gfx) gl_freeTexture(effect->gfx);
+  if(effect->name != NULL)  free(effect->name);
+  if(effect->gfx != NULL)   gl_freeTexture(effect->gfx);
 }
 
 int spfx_get(char* name) {
diff --git a/src/toolkit.c b/src/toolkit.c
index c65c848..c699db9 100644
--- a/src/toolkit.c
+++ b/src/toolkit.c
@@ -511,6 +511,7 @@ unsigned int window_create(char* name, const int x, const int y,
     wdw->y = SCREEN_H - windows[nwindows].h + (double)y;
   else wdw->y = (double)y;
 
+  /* Widgets. */
   wdw->widgets  = NULL;
   wdw->nwidgets = 0;
 
@@ -576,6 +577,12 @@ void window_destroy(const unsigned int wid) {
       free(windows[i].widgets);
       break;
     }
+
+  if(i == nwindows) { /* Not found. */
+    WARN("Window of id '%u' not found in window stack!", wid);
+    return;
+  }
+
   /* Move the other windows down a layer. */
   for(; i<(nwindows-1); i++)
     windows[i] = windows[i+1];