diff --git a/SMILEBASIC/builtinfunctions.d b/SMILEBASIC/builtinfunctions.d
index cfcccb1..097b991 100644
--- a/SMILEBASIC/builtinfunctions.d
+++ b/SMILEBASIC/builtinfunctions.d
@@ -3051,6 +3051,13 @@ class BuiltinFunction
             throw new OutOfRange("KEY", 1);
         key = new Array!wchar(cast(wchar[])p.functionKey[index]);
     }
+    import otya.smilebasic.dialog;
+    import otya.smilebasic.project;
+    static void DIALOG(PetitComputer p, wstring text)
+    {
+        auto dialog = new Dialog(p);
+        p.project.result = cast(DialogResult)dialog.show(text);
+    }
     //alias void function(PetitComputer, Value[], Value[]) BuiltinFunc;
     static BuiltinFunctions[wstring] builtinFunctions;
     static wstring getBasicName(BFD)(const wstring def)
diff --git a/SMILEBASIC/petitcomputer.d b/SMILEBASIC/petitcomputer.d
index 8e0c3a0..11754fc 100644
--- a/SMILEBASIC/petitcomputer.d
+++ b/SMILEBASIC/petitcomputer.d
@@ -1626,8 +1626,9 @@ class PetitComputer
             return currentDisplay.rect[1];
         }
         auto rect = currentDisplay.rect[0];
-        rect.y += rect.h;
+        rect.y = 0;
         currentDisplay.windowSize.height += rect.h;
+        currentDisplay.yoffset = currentDisplay.windowSize.height;
         updateWindowSize();
         return rect;
     }
@@ -1639,6 +1640,7 @@ class PetitComputer
         }
         auto rect = currentDisplay.rect[0];
         currentDisplay.windowSize.height -= rect.h;
+        currentDisplay.yoffset = currentDisplay.windowSize.height;
         updateWindowSize();
     }
     //プチコン内部表現はRGB5_A1