xW: handle WM_SYSCOLORCHANGE

xW/xW.cpp

@@ -499,7 +499,7 @@ convert_item_formatting(Relay::ItemData *item, CHARFORMAT2 &cf, bool &inverse)
 }
 
 static std::vector<BufferLineItem>
-convert_items(std::vector<std::unique_ptr<Relay::ItemData>> &items)
+convert_items(const std::vector<std::unique_ptr<Relay::ItemData>> &items)
 {
 	CHARFORMAT2 cf = default_charformat();
 	std::vector<BufferLineItem> result;
@@ -1627,6 +1627,21 @@ window_proc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 		if (auto b = buffer_by_name(g.buffer_current))
 			refresh_buffer(*b);
 		return 0;
+	case WM_SYSCOLORCHANGE:
+		// The topic would flicker with WS_EX_TRANSPARENT.
+		// The buffer only changed its text colour, not background.
+		SendMessage(g.hwndTopic,
+			EM_SETBKGNDCOLOR, 0, GetSysColor(COLOR_3DFACE));
+		SendMessage(g.hwndBuffer,
+			EM_SETBKGNDCOLOR, 1, 0);
+
+		// XXX: This is incomplete, we'd have to run convert_items() again;
+		// essentially only COLOR_GRAYTEXT is reloaded in here.
+		if (auto b = buffer_by_name(g.buffer_current))
+			refresh_buffer(*b);
+
+		// Pass it to all child windows, through DefWindowProc().
+		break;
 	case WM_ACTIVATE:
 		if (LOWORD(wParam) == WA_INACTIVE)
 			g.hwndLastFocused = GetFocus();