Transpose tool will only transpose initial key signature …

src/engraving/dom/transpose.cpp

@@ -489,7 +489,7 @@ bool Score::transpose(TransposeMode mode, TransposeDirection direction, Key trKe
             } else if (e->isKeySig() && trKeys && mode != TransposeMode::DIATONICALLY) {
                 KeySig* ks = toKeySig(e);
                 Fraction tick = segment->tick();
-                bool startKey = tick == s1->tick();
+                bool startKey = tick == s1->tick() && !isFirstSystemKeySig(ks);
                 bool addKey = ks->isChange();
                 if ((startKey || addKey) && !ks->isAtonal()) {
                     Staff* staff = ks->staff();

src/engraving/dom/utils.cpp

@@ -30,6 +30,7 @@
 #include "chord.h"
 #include "chordrest.h"
 #include "clef.h"
+#include "keysig.h"
 #include "measure.h"
 #include "note.h"
 #include "page.h"
@@ -1334,4 +1335,16 @@ String formatUniqueExcerptName(const String& baseName, const StringList& allExce
 
     return result;
 }
+
+bool isFirstSystemKeySig(const KeySig* ks)
+{
+    if (!ks) {
+        return false;
+    }
+    const System* sys = ks->measure()->system();
+    if (!sys) {
+        return false;
+    }
+    return ks->tick() == sys->firstMeasure()->tick();
+}
 }

src/engraving/dom/utils.h

@@ -31,12 +31,13 @@
 
 namespace mu::engraving {
 class Chord;
+class EngravingItem;
+class KeySig;
 class Note;
 class Rest;
 class Segment;
 class System;
 class Tuplet;
-class EngravingItem;
 
 enum class Key;
 
@@ -92,5 +93,7 @@ extern void collectChordsOverlappingRests(Segment* segment, staff_idx_t staffIdx
 extern Interval ornamentIntervalToGeneralInterval(OrnamentInterval interval);
 
 extern String formatUniqueExcerptName(const String& baseName, const StringList& allExcerptLowerNames);
+
+extern bool isFirstSystemKeySig(const KeySig* ks);
 } // namespace mu::engraving
 #endif