[LyX/master] Fix ticket #13345 (again)

[Koji Yokota]

commit 87c7020b9ef4a65a3ed6e1696dda679a534004e6
Author: Koji Yokota <yokota at lyx.org>
Date:   Sat Jul 4 12:23:08 2026 +0900

    Fix ticket #13345 (again)
---
 src/frontends/qt/GuiInputMethod.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/frontends/qt/GuiInputMethod.cpp b/src/frontends/qt/GuiInputMethod.cpp
index 86b1424202..8d08821856 100644
--- a/src/frontends/qt/GuiInputMethod.cpp
+++ b/src/frontends/qt/GuiInputMethod.cpp
@@ -737,9 +737,11 @@ pos_type GuiInputMethod::pickNextSegFromTurnout(pos_type next_seg_pos, size_type
 				        << it->start_ << ", "
 				        << it->start_ + it->length_ << ")");
 				for (auto it2 = d->seg_turnout_.begin();
-				     it2 != d->seg_turnout_.end(); it2++)
+				     it2 != d->seg_turnout_.end();)
 					if (*it == *it2)
 						d->seg_turnout_.erase(it2);
+					else
+						++it2;
 			}
 		}
 	}