From 34ea6c5b3e1744e56393a3af9d0710026e2290d7 Mon Sep 17 00:00:00 2001
From: vserediuk <65343640+vserediuk@users.noreply.github.com>
Date: Thu, 19 Mar 2026 20:46:20 +0100
Subject: [PATCH] Fix excessive combining marks causing GPU overload

Extend IsDiacritic() to recognize Mark_Enclosing and Mark_SpacingCombining Unicode categories, so the existing per-character combining mark limit (kMaxDiacAfterSymbol = 2) applies to all types of combining characters.

Previously only Mark_NonSpacing was checked, allowing characters like U+20DD (COMBINING ENCLOSING CIRCLE) to bypass the limit and stack hundreds of times on a single base character, causing GPU overload and rendering corruption.
---
 ui/text/text.cpp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/ui/text/text.cpp b/ui/text/text.cpp
index d13b96810..badcd6e66 100644
--- a/ui/text/text.cpp
+++ b/ui/text/text.cpp
@@ -2011,8 +2011,11 @@ bool IsSpace(QChar ch) {
 		|| (ch == QChar::Tabulation);
 }
 
-bool IsDiacritic(QChar ch) { // diacritic and variation selectors
-	return (ch.category() == QChar::Mark_NonSpacing)
+bool IsDiacritic(QChar ch) { // diacritic, combining and variation selectors
+	const auto category = ch.category();
+	return (category == QChar::Mark_NonSpacing)
+		|| (category == QChar::Mark_Enclosing)
+		|| (category == QChar::Mark_SpacingCombining)
 		|| (ch.unicode() == 1652)
 		|| (ch.unicode() >= 64606 && ch.unicode() <= 64611);
 }