From d2376f0203884428d7aba4f49b9034d5a0bc245e Mon Sep 17 00:00:00 2001
From: nimetu <nimetu@gmail.com>
Date: Sat, 22 Jan 2022 00:59:48 +0200
Subject: [PATCH] Ensure selected item is visible after menu becomes active

---
 nel/include/nel/gui/group_menu.h |  2 ++
 nel/src/gui/ctrl_scroll.cpp      |  4 ++++
 nel/src/gui/group_menu.cpp       | 22 +++++++++++++++++++---
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/nel/include/nel/gui/group_menu.h b/nel/include/nel/gui/group_menu.h
index c7bd017ae..25ec43f96 100644
--- a/nel/include/nel/gui/group_menu.h
+++ b/nel/include/nel/gui/group_menu.h
@@ -289,6 +289,8 @@ namespace NLGUI
 
 		sint32							_MaxVisibleLine; // -1 == no limit
 
+		bool							_ScrollToView;
+
 		friend class CGroupMenu;
 	private:
 		/** Clone this menu, and set its new father
diff --git a/nel/src/gui/ctrl_scroll.cpp b/nel/src/gui/ctrl_scroll.cpp
index 28d7f2fed..0587e5caf 100644
--- a/nel/src/gui/ctrl_scroll.cpp
+++ b/nel/src/gui/ctrl_scroll.cpp
@@ -1432,6 +1432,8 @@ namespace NLGUI
 		childElement->getCorner(childX, childY, childHotSpot);
 		if (_Vertical)
 		{
+			// remove previous scroll offset from child
+			childY -= _Target->getOfsY();
 			sint32	maxHReal= _Target->getMaxHReal();
 			sint32	hReal=	  _Target->getHReal();
 			if(hReal > maxHReal)
@@ -1473,6 +1475,8 @@ namespace NLGUI
 		}
 		else
 		{
+			// remove previous scroll offset from child
+			childX -= _Target->getOfsX();
 			sint32	maxWReal= _Target->getMaxWReal();
 			sint32	wReal=	  _Target->getWReal();
 			if(wReal > maxWReal)
diff --git a/nel/src/gui/group_menu.cpp b/nel/src/gui/group_menu.cpp
index 9398ea4b1..72bf3c8c9 100644
--- a/nel/src/gui/group_menu.cpp
+++ b/nel/src/gui/group_menu.cpp
@@ -133,6 +133,7 @@ namespace NLGUI
 		_Selected = -1;
 		_MaxVisibleLine = -1;
 		_ScrollBar = NULL;
+		_ScrollToView = false;
 	}
 
 	// ------------------------------------------------------------------------------------------------
@@ -590,6 +591,7 @@ namespace NLGUI
 				_GroupList->setMaxH(widgetMaxH*_MaxVisibleLine+_GroupList->getSpace()*(_MaxVisibleLine-1));
 				if (_ScrollBar == NULL)
 				{
+					_ScrollToView = true;
 					_ScrollBar = new CCtrlScroll(CViewBase::TCtorParam());
 					_ScrollBar->setParent (this);
 					_ScrollBar->setParentPos (_GroupList);
@@ -897,6 +899,16 @@ namespace NLGUI
 			_SelectionView->setH (refElmHReal);
 			_SelectionView->setY (refElmYReal - this->getYReal());
 		}
+
+		// initial scroll after becoming active
+		if (_ScrollBar && _ScrollToView)
+		{
+			_ScrollToView = false;
+			if (_Selected != -1 && _Lines[_Selected].ViewText != NULL)
+				_ScrollBar->ensureVisible(_Lines[_Selected].ViewText, Hotspot_Tx, Hotspot_Mx);
+			else
+				_ScrollBar->setTrackPos(_GroupList->getHReal());
+		}
 	}
 
 	// ------------------------------------------------------------------------------------------------
@@ -1664,10 +1676,10 @@ namespace NLGUI
 			}
 		}
 
-		if(_ScrollBar && _GroupList)
-			_ScrollBar->setTrackPos(_GroupList->getHReal());
-
 		CGroupFrame::setActive(state);
+
+		// handle scrolling in next updateCoords() call
+		_ScrollToView = true;
 	}
 
 	// ------------------------------------------------------------------------------------------------
@@ -2538,6 +2550,10 @@ namespace NLGUI
 
 		CGroupFrame::setActive (state);
 
+		// skip rest if being hidden
+		if (!state)
+			return;
+
 		// must recompute now the pos of the menu
 		uint32 i;
 		for (i = 0; i < _ChildrenGroups.size(); ++i)