diff --git a/uppsrc/ide/IncludeTrick.cpp b/uppsrc/ide/IncludeTrick.cpp
index 6f54f6d13..f3d9a415a 100644
--- a/uppsrc/ide/IncludeTrick.cpp
+++ b/uppsrc/ide/IncludeTrick.cpp
@@ -19,6 +19,7 @@ void AssistEditor::SyncMaster()
 
 	if(AssistDiagnostics) {
 		PutConsole("Master source " << editfile << " -> " << master_source);
+		PutConsole("Master chain " << AsString(master_chain));
 		ppi.WhenBlitzBlock = [=](const String& inc, const String& path) {
 			PutConsole(String() << inc << " blocks BLITZ of " << path);
 		};
diff --git a/uppsrc/ide/clang/Indexer.cpp b/uppsrc/ide/clang/Indexer.cpp
index bd804b418..7c0bb2c1d 100644
--- a/uppsrc/ide/clang/Indexer.cpp
+++ b/uppsrc/ide/clang/Indexer.cpp
@@ -11,7 +11,7 @@ String FindMasterSource(PPInfo& ppi, const Workspace& wspc, const String& header
 	LTIMING("FindMasterSource");
 	String header_file = NormalizePath(header_file_);
 
-	for(int speculative = 0; speculative < 2; speculative++) {
+	for(int pass = 0; pass < 3; pass++) {
 		VectorMap<String, Time> deps;
 		ArrayMap<String, Index<String>> dics;
 		for(int i : wspc.use_order) {
@@ -20,8 +20,12 @@ String FindMasterSource(PPInfo& ppi, const Workspace& wspc, const String& header
 			for(int i = 0; i < pk.file.GetCount(); i++) {
 				String path = SourcePath(pk_name, pk.file[i]);
 				if(!pk.file[i].separator && ppi.FileExists(path) && !PathIsEqual(header_file, path) &&
-				   IsCppSourceFile(path) && GetFileLength(path) < 4000000) {
-					ppi.GatherDependencies(path, deps, dics, speculative);
+				   IsCppSourceFile(path) &&
+				   (pass == 2 || // last chance speculative run, any folder
+				    pass == 0 && GetFileFolder(path) == GetFileFolder(header_file) || // prefer source from the same folder first
+				    pass == 1 && GetFileFolder(path) != GetFileFolder(header_file)) &&
+				   GetFileLength(path) < 4000000) {
+					ppi.GatherDependencies(path, deps, dics, pass > 1);
 					if(deps.Find(header_file) >= 0)
 						return path;
 				}
@@ -50,7 +54,7 @@ const VectorMap<String, Time>& FindMasterSourceCached(PPInfo& ppi, const Workspa
                                                       VectorMap<String, MasterSourceCacheRecord>& cache)
 {
 	String header_file = NormalizePath(header_file_);
-	
+
 	if(cache.GetCount() > 2000) // 2000 cached headers is enough for everybody, right?
 		cache.Clear();