diff --git a/src/terminal/terminalfunctions.cc b/src/terminal/terminalfunctions.cc
index c167c63..a1902a8 100644
--- a/src/terminal/terminalfunctions.cc
+++ b/src/terminal/terminalfunctions.cc
@@ -282,6 +282,12 @@ static bool *get_DEC_mode( int param, Framebuffer *fb ) {
   return NULL;
 }
 
+/* helper for CSI_DECSM and CSI_DECRM */
+void set_if_available( bool *mode, bool value )
+{
+  if ( mode ) { *mode = value; }
+}
+
 /* set private mode */
 void CSI_DECSM( Framebuffer *fb, Dispatcher *dispatch )
 {
@@ -289,21 +295,16 @@ void CSI_DECSM( Framebuffer *fb, Dispatcher *dispatch )
     int param = dispatch->getparam( i, 0 );
 
     if ( (param == 1000) || (param == 1002) ) {
-      // clear the other mouse modes before setting this one
-      bool *c_mode = get_DEC_mode( 1000, fb );
-      if ( c_mode ) { *c_mode = false; }
-      *c_mode = get_DEC_mode( 1002, fb );
-      if ( c_mode ) { *c_mode = false; }
-      *c_mode = get_DEC_mode( 1005, fb );
-      if ( c_mode ) { *c_mode = false; }
-      *c_mode = get_DEC_mode( 1006, fb );
-      if ( c_mode ) { *c_mode = false; }
+      /* we believe all mouse modes should be set to false
+	 when either of these two modes are enabled */
+      /* XXX can we cite something for this? -KJW 15Dec2014 */
+      set_if_available( get_DEC_mode( 1000, fb ), false );
+      set_if_available( get_DEC_mode( 1002, fb ), false );
+      set_if_available( get_DEC_mode( 1005, fb ), false );
+      set_if_available( get_DEC_mode( 1006, fb ), false );
     }
 
-    bool *mode = get_DEC_mode( param, fb );
-    if ( mode ) {
-      *mode = true;
-    }
+    set_if_available( get_DEC_mode( param, fb ), true );
   }
 }
 
@@ -311,10 +312,7 @@ void CSI_DECSM( Framebuffer *fb, Dispatcher *dispatch )
 void CSI_DECRM( Framebuffer *fb, Dispatcher *dispatch )
 {
   for ( int i = 0; i < dispatch->param_count(); i++ ) {
-    bool *mode = get_DEC_mode( dispatch->getparam( i, 0 ), fb );
-    if ( mode ) {
-      *mode = false;
-    }
+    set_if_available( get_DEC_mode( dispatch->getparam( i, 0 ), fb ), false );
   }
 }