diff --git a/dlls/usp10/usp10.c b/dlls/usp10/usp10.c
index 0a269961b78..6975a49caad 100644
--- a/dlls/usp10/usp10.c
+++ b/dlls/usp10/usp10.c
@@ -3875,6 +3875,7 @@ const SIZE * WINAPI ScriptString_pSize(SCRIPT_STRING_ANALYSIS ssa)
             for (j = 0; j < analysis->glyphs[i].numGlyphs; j++)
                 analysis->sz.cx += analysis->glyphs[i].piAdvance[j];
         }
+        analysis->flags |= SCRIPT_STRING_ANALYSIS_FLAGS_SIZE;
     }
     return &analysis->sz;
 }