Address CodeRabbit review feedback

- llscrollbar: clear the residue when a sub-notch wheel event is forwarded to a
  parent scroller at a boundary, so reversing direction responds immediately
  instead of first unwinding leftover fraction.
- lldxhardware: QueryInterface to IDXGIAdapter3 (not a reinterpret_cast of the
  IDXGIAdapter from EnumAdapters), and zero-init + HRESULT-check
  QueryVideoMemoryInfo before reading info.Budget.
- llappviewersdl: SendMessageTimeout (SMTO_ABORTIFHUNG, 2s) for the second-
  instance SLURL handoff so a hung primary can't block startup; require delivery
  before treating the URL as handed off.
- llviewercontrol / llviewerwindow: clamp NumpadControl to the valid enum range
  before the e_numpad_distinct cast.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: RyeMutt

indra/llui/llscrollbar.cpp

@@ -428,11 +428,21 @@ bool LLScrollbar::scrollByWheel(F32 precise)
     // that.
     if (precise > 0.f)
     {
-        return mDocPos < getDocPosMax();
+        if (mDocPos < getDocPosMax())
+        {
+            return true;
+        }
+        mScrollWheelResidue = 0.f; // forwarding to parent; don't keep partial progress
+        return false;
     }
     if (precise < 0.f)
     {
-        return mDocPos > 0;
+        if (mDocPos > 0)
+        {
+            return true;
+        }
+        mScrollWheelResidue = 0.f; // forwarding to parent; don't keep partial progress
+        return false;
     }
     return false;
 }

indra/llwindow/lldxhardware.cpp

@@ -486,11 +486,11 @@ void LLDXHardware::updateVRAMBudgetFromDXGI()
     }
     else
     {
-        IDXGIAdapter3* p_dxgi_adapter = nullptr;
+        IDXGIAdapter* p_dxgi_adapter = nullptr;
         UINT graphics_adapter_index = 0;
         while (true)
         {
-            res = p_factory->EnumAdapters(graphics_adapter_index, reinterpret_cast<IDXGIAdapter**>(&p_dxgi_adapter));
+            res = p_factory->EnumAdapters(graphics_adapter_index, &p_dxgi_adapter);
             if (FAILED(res))
             {
                 if (graphics_adapter_index == 0)
@@ -502,8 +502,25 @@ void LLDXHardware::updateVRAMBudgetFromDXGI()
             {
                 if (graphics_adapter_index == 0) // Should it check largest one isntead of first?
                 {
-                    DXGI_QUERY_VIDEO_MEMORY_INFO info;
-                    p_dxgi_adapter->QueryVideoMemoryInfo(0, DXGI_MEMORY_SEGMENT_GROUP_LOCAL, &info);
+                    // EnumAdapters hands back an IDXGIAdapter; QueryInterface up
+                    // to IDXGIAdapter3 for QueryVideoMemoryInfo (Win10+). Zero-init
+                    // info and check the HRESULT so a failed query can't feed
+                    // garbage Budget into the VRAM estimate (it just leaves it 0).
+                    IDXGIAdapter3* p_dxgi_adapter3 = nullptr;
+                    DXGI_QUERY_VIDEO_MEMORY_INFO info = {};
+                    if (SUCCEEDED(p_dxgi_adapter->QueryInterface(__uuidof(IDXGIAdapter3), (void**)&p_dxgi_adapter3)) && p_dxgi_adapter3)
+                    {
+                        if (FAILED(p_dxgi_adapter3->QueryVideoMemoryInfo(0, DXGI_MEMORY_SEGMENT_GROUP_LOCAL, &info)))
+                        {
+                            info = {};
+                            LL_WARNS() << "QueryVideoMemoryInfo failed" << LL_ENDL;
+                        }
+                        p_dxgi_adapter3->Release();
+                    }
+                    else
+                    {
+                        LL_WARNS() << "IDXGIAdapter3 unavailable; skipping DXGI VRAM budget" << LL_ENDL;
+                    }
 
                     // Alternatively use GetDesc from below to get adapter's memory
                     UINT64 budget_mb = info.Budget / (1024 * 1024);

indra/newview/llappviewersdl.cpp

@@ -1032,9 +1032,17 @@ bool LLAppViewerSDL::sendURLToOtherInstance(const std::string& url)
         cds.cbData                        = static_cast<DWORD>(url.length()) + 1;
         cds.lpData                        = (void*)url.c_str();
 
-        LRESULT msg_result = SendMessage(other_window, WM_COPYDATA, NULL, (LPARAM)&cds);
-        LL_DEBUGS() << "SendMessage(WM_COPYDATA) to other window '" << getWindowTitle() << "' returned " << msg_result << LL_ENDL;
-        return true;
+        // SendMessageTimeout (not SendMessage) so a hung/busy primary instance
+        // can't block this instance's startup; SMTO_ABORTIFHUNG bails fast. Our
+        // WM_COPYDATA handler returns TRUE on receipt, so require both a
+        // successful send and a non-zero result before treating the URL as
+        // handed off — otherwise fall through (return false) and handle it here.
+        DWORD_PTR msg_result = 0;
+        LRESULT sent = SendMessageTimeout(other_window, WM_COPYDATA, NULL, (LPARAM)&cds,
+                                          SMTO_ABORTIFHUNG, 2000, &msg_result);
+        LL_DEBUGS() << "SendMessageTimeout(WM_COPYDATA) to other window '" << getWindowTitle()
+                    << "' sent=" << sent << " result=" << msg_result << LL_ENDL;
+        return sent != 0 && msg_result != 0;
     }
     return false;
 }

indra/newview/llviewercontrol.cpp

@@ -193,7 +193,10 @@ static bool handleNumpadControlChanged(const LLSD& newvalue)
 {
     if (gKeyboard)
     {
-        gKeyboard->setNumpadDistinct(static_cast<LLKeyboard::e_numpad_distinct>(newvalue.asInteger()));
+        // Clamp persisted/out-of-range values to the valid enum range so an
+        // edited settings file can't push the keyboard into an undefined mode.
+        S32 mode = llclamp(newvalue.asInteger(), (S32)LLKeyboard::ND_NEVER, (S32)LLKeyboard::ND_NUMLOCK_ON);
+        gKeyboard->setNumpadDistinct(static_cast<LLKeyboard::e_numpad_distinct>(mode));
     }
     return true;
 }

indra/newview/llviewerwindow.cpp

@@ -2317,7 +2317,8 @@ LLViewerWindow::LLViewerWindow(const Params& p)
     // keeps it in sync on subsequent changes.
     if (gKeyboard)
     {
-        gKeyboard->setNumpadDistinct(static_cast<LLKeyboard::e_numpad_distinct>(gSavedSettings.getS32("NumpadControl")));
+        S32 numpad_mode = llclamp(gSavedSettings.getS32("NumpadControl"), (S32)LLKeyboard::ND_NEVER, (S32)LLKeyboard::ND_NUMLOCK_ON);
+        gKeyboard->setNumpadDistinct(static_cast<LLKeyboard::e_numpad_distinct>(numpad_mode));
     }
 
     mDebugText = new LLDebugText(this);