move and fix scrolling to layout

Scrolling was hardcoded to 3ds sCrEeNhEiGhT wTh

include/pd/ui7/flags.hpp

@@ -58,6 +58,8 @@ enum UI7MenuFlags_ {
 enum UI7LayoutFlags_ {
   UI7LayoutFlags_None = 0,              ///< No Flags used
   UI7LayoutFlags_UseClipRect = 1 << 0,  ///< Enable ClipRect
+  UI7LayoutFlags_HzScrolling = 1 << 1,  ///< Scrolling Horizontal
+  UI7LayoutFlags_VtScrolling = 1 << 2,  ///< Scrolling Vertical
 };
 
 /** UI7 Context Flags */

include/pd/ui7/layout.hpp

@@ -163,6 +163,8 @@ class PD_API Layout {
   void SetAlign(UI7Align a) { Alignment = a; }
   void NextAlign(UI7Align a) { TempAlign = a; }
 
+  void HandleScrolling();
+
   void Update();
 
   fvec2 DbgScrollOffset() { return ScrollOffset; }

include/pd/ui7/menu.hpp

@@ -110,7 +110,6 @@ class PD_API Menu {
   void EndTreeNode();
 
   void HandleFocus();
-  void HandleScrolling();
   void HandleTitlebarActions();
   void DrawBaseLayout();