(svn r22800) -Fix (r22796): don't run the scanning threaded when there is no reason to do so (no UI to update)

src/newgrf_config.cpp

@@ -19,6 +19,8 @@
 #include "window_func.h"
 #include "progress.h"
 #include "thread/thread.h"
+#include "blitter/factory.hpp"
+#include "network/network.h"
 
 #include "fileio_func.h"
 #include "fios.h"
@@ -694,9 +696,11 @@ void DoScanNewGRFFiles(void *callback)
  */
 void ScanNewGRFFiles(NewGRFScanCallback *callback)
 {
-	if (!ThreadObject::New(&DoScanNewGRFFiles, callback, NULL)) {
+	if (BlitterFactoryBase::GetCurrentBlitter()->GetScreenDepth() == 0 || _network_dedicated || !ThreadObject::New(&DoScanNewGRFFiles, callback, NULL)) {
 		_modal_progress_work_mutex->EndCritical();
+		_modal_progress_paint_mutex->EndCritical();
 		DoScanNewGRFFiles(callback);
+		_modal_progress_paint_mutex->BeginCritical();
 		_modal_progress_work_mutex->BeginCritical();
 	}
 }