#2454 Scrolling by the mouse wheel does not scroll up on the unopened Destination field

indra/llui/llcombobox.cpp

@@ -498,9 +498,9 @@ void LLComboBox::setButtonVisible(bool visible)
     }
 }
 
-bool LLComboBox::setCurrentByIndex( S32 index )
+bool LLComboBox::setCurrentByIndex(S32 index)
 {
-    bool found = mList->selectNthItem( index );
+    bool found = mList->selectNthItem(index);
     if (found)
     {
         setLabel(getSelectedItemLabel());
@@ -511,14 +511,53 @@ bool LLComboBox::setCurrentByIndex( S32 index )
 
 S32 LLComboBox::getCurrentIndex() const
 {
-    LLScrollListItem* item = mList->getFirstSelected();
-    if( item )
+    if (LLScrollListItem* item = mList->getFirstSelected())
     {
-        return mList->getItemIndex( item );
+        return mList->getItemIndex(item);
     }
     return -1;
 }
 
+bool LLComboBox::selectNextItem()
+{
+    S32 last_index = getItemCount() - 1;
+    if (last_index < 0)
+        return false;
+
+    S32 current_index = getCurrentIndex();
+    if (current_index >= last_index)
+        return false;
+
+    S32 new_index = llmax(current_index, -1);
+    while (++new_index <= last_index)
+    {
+        if (setCurrentByIndex(new_index))
+            return true;
+    }
+
+    return false;
+}
+
+bool LLComboBox::selectPrevItem()
+{
+    S32 last_index = getItemCount() - 1;
+    if (last_index < 0)
+        return false;
+
+    S32 current_index = getCurrentIndex();
+    if (!current_index)
+        return false;
+
+    S32 new_index = current_index > 0 ? current_index : last_index + 1;
+    while (--new_index >= 0)
+    {
+        if (setCurrentByIndex(new_index))
+            return true;
+    }
+
+    return false;
+}
+
 void LLComboBox::setEnabledByValue(const LLSD& value, bool enabled)
 {
     LLScrollListItem *found = mList->getItem(value);
@@ -878,15 +917,46 @@ bool LLComboBox::handleUnicodeCharHere(llwchar uni_char)
 // virtual
 bool LLComboBox::handleScrollWheel(S32 x, S32 y, S32 clicks)
 {
-    if (mList->getVisible()) return mList->handleScrollWheel(x, y, clicks);
+    if (mList->getVisible())
+    {
+        return mList->handleScrollWheel(x, y, clicks);
+    }
+
     if (mAllowTextEntry) // We might be editable
+    {
         if (!mList->getFirstSelected()) // We aren't in the list, don't kill their text
+        {
             return false;
+        }
+    }
 
-    setCurrentByIndex(llclamp(getCurrentIndex() + clicks, 0, getItemCount() - 1));
-    prearrangeList();
-    onCommit();
-    return true;
+    S32 current_index = getCurrentIndex();
+    if (clicks > 0)
+    {
+        for (S32 i = 0; i < clicks; ++i)
+        {
+            if (!selectNextItem())
+                break;
+        }
+    }
+    else
+    {
+        for (S32 i = 0; i < -clicks; ++i)
+        {
+            if (!selectPrevItem())
+                break;
+        }
+    }
+    S32 new_index = getCurrentIndex();
+
+    if (new_index != current_index)
+    {
+        prearrangeList();
+        onCommit();
+        return true;
+    }
+
+    return false;
 }
 
 void LLComboBox::setTextEntry(const LLStringExplicit& text)

indra/llui/llcombobox.h

@@ -163,9 +163,12 @@ class LLComboBox
 
     bool            remove(const std::string& name);    // remove item "name", return true if found and removed
 
-    bool            setCurrentByIndex( S32 index );
+    bool            setCurrentByIndex(S32 index);
     S32             getCurrentIndex() const;
 
+    bool            selectNextItem();
+    bool            selectPrevItem();
+
     void            setEnabledByValue(const LLSD& value, bool enabled);
 
     void            createLineEditor(const Params&);

indra/llui/llscrolllistctrl.cpp

@@ -889,13 +889,13 @@ bool LLScrollListCtrl::selectFirstItem()
 
 // Deselects all other items
 // virtual
-bool LLScrollListCtrl::selectNthItem( S32 target_index )
+bool LLScrollListCtrl::selectNthItem(S32 target_index)
 {
     return selectItemRange(target_index, target_index);
 }
 
 // virtual
-bool LLScrollListCtrl::selectItemRange( S32 first_index, S32 last_index )
+bool LLScrollListCtrl::selectItemRange(S32 first_index, S32 last_index)
 {
     if (mItemList.empty())
     {
@@ -905,28 +905,24 @@ bool LLScrollListCtrl::selectItemRange( S32 first_index, S32 last_index )
     // make sure sort is up to date
     updateSort();
 
-    S32 listlen = (S32)mItemList.size();
-    first_index = llclamp(first_index, 0, listlen-1);
-
-    if (last_index < 0)
-        last_index = listlen-1;
-    else
-        last_index = llclamp(last_index, first_index, listlen-1);
+    S32 bottom = (S32)mItemList.size() - 1;
+    first_index = llclamp(first_index, 0, bottom);
+    last_index = last_index < 0 ? bottom : llclamp(last_index, first_index, bottom);
 
     bool success = false;
     S32 index = 0;
     for (item_list::iterator iter = mItemList.begin(); iter != mItemList.end(); )
     {
         LLScrollListItem *itemp = *iter;
-        if(!itemp)
+        if (!itemp)
         {
             iter = mItemList.erase(iter);
-            continue ;
+            continue;
         }
 
-        if( index >= first_index && index <= last_index )
+        if (index >= first_index && index <= last_index)
         {
-            if( itemp->getEnabled() )
+            if (itemp->getEnabled())
             {
                 // TODO: support range selection for cells
                 selectItem(itemp, -1, false);