diff --git a/novelwriter/common.py b/novelwriter/common.py
index 7cb6c5e0..a4e37f62 100644
--- a/novelwriter/common.py
+++ b/novelwriter/common.py
@@ -40,7 +40,7 @@ from PyQt6.QtCore import QCoreApplication, QMimeData, QUrl
 from PyQt6.QtGui import QAction, QDesktopServices, QFont, QFontDatabase, QFontInfo
 from PyQt6.QtWidgets import QMenu, QMenuBar, QWidget
 
-from novelwriter.constants import nwConst, nwLabels, nwUnicode, trConst
+from novelwriter.constants import nwConst, nwLabels, nwQuotes, nwUnicode, trConst
 from novelwriter.enum import nwItemClass, nwItemLayout, nwItemType
 from novelwriter.error import logException
 
@@ -298,6 +298,15 @@ def uniqueCompact(text: str) -> str:
     return "".join(sorted(set(compact(text))))
 
 
+def processDialogSymbols(symbols: str) -> str:
+    """Process dialogue line symbols."""
+    result = ""
+    for c in uniqueCompact(symbols):
+        if c in nwQuotes.ALLOWED:
+            result += c
+    return result
+
+
 def elide(text: str, length: int) -> str:
     """Elide a piece of text to a maximum length."""
     if len(text) > (cut := max(4, length)):
diff --git a/novelwriter/config.py b/novelwriter/config.py
index 0597c82e..d820c66a 100644
--- a/novelwriter/config.py
+++ b/novelwriter/config.py
@@ -42,7 +42,7 @@ from PyQt6.QtWidgets import QApplication
 
 from novelwriter.common import (
     NWConfigParser, checkInt, checkPath, describeFont, fontMatcher,
-    formatTimeStamp
+    formatTimeStamp, processDialogSymbols
 )
 from novelwriter.constants import nwFiles, nwHtmlUnicode, nwQuotes, nwUnicode
 from novelwriter.error import formatException, logException
@@ -680,7 +680,7 @@ class Config:
         self.showFullPath    = conf.rdBool(sec, "showfullpath", self.showFullPath)
         self.dialogStyle     = conf.rdInt(sec, "dialogstyle", self.dialogStyle)
         self.allowOpenDial   = conf.rdBool(sec, "allowopendial", self.allowOpenDial)
-        self.dialogLine      = conf.rdStr(sec, "dialogline", self.dialogLine)
+        dialogLine           = conf.rdStr(sec, "dialogline", self.dialogLine)
         narratorBreak        = conf.rdStr(sec, "narratorbreak", self.narratorBreak)
         narratorDialog       = conf.rdStr(sec, "narratordialog", self.narratorDialog)
         self.altDialogOpen   = conf.rdStr(sec, "altdialogopen", self.altDialogOpen)
@@ -721,6 +721,7 @@ class Config:
             logger.info("Using straight double quotes, so disabling auto-replace")
             self.doReplaceDQuote = False
 
+        self.dialogLine = processDialogSymbols(dialogLine)
         self.narratorBreak = narratorBreak if narratorBreak in nwQuotes.DASHES else ""
         self.narratorDialog = narratorDialog if narratorDialog in nwQuotes.DASHES else ""
 
diff --git a/novelwriter/constants.py b/novelwriter/constants.py
index 72ba4b90..16c5a082 100644
--- a/novelwriter/constants.py
+++ b/novelwriter/constants.py
@@ -512,6 +512,12 @@ class nwQuotes:
         "\u2015": QT_TRANSLATE_NOOP("Constant", "Horizontal bar"),
     }
 
+    ALLOWED: Final[list[str]] = [
+        "\u0027", "\u0022", "\u2018", "\u2019", "\u201a", "\u201b", "\u201c", "\u201d", "\u201e",
+        "\u201f", "\u2e42", "\u2039", "\u203a", "\u00ab", "\u00bb", "\u300c", "\u300d", "\u300e",
+        "\u300f", "\u2013", "\u2014", "\u2015",
+    ]
+
 
 class nwUnicode:
     """Supported unicode character constants and their HTML equivalents."""
diff --git a/novelwriter/dialogs/preferences.py b/novelwriter/dialogs/preferences.py
index 166b98be..f98374af 100644
--- a/novelwriter/dialogs/preferences.py
+++ b/novelwriter/dialogs/preferences.py
@@ -34,7 +34,7 @@ from PyQt6.QtWidgets import (
 )
 
 from novelwriter import CONFIG, SHARED
-from novelwriter.common import compact, describeFont, uniqueCompact
+from novelwriter.common import compact, describeFont, processDialogSymbols, uniqueCompact
 from novelwriter.config import DEF_GUI, DEF_ICONS, DEF_SYNTAX, DEF_TREECOL
 from novelwriter.constants import nwLabels, nwQuotes, nwUnicode, trConst
 from novelwriter.dialogs.quotes import GuiQuoteSelect
@@ -1033,7 +1033,7 @@ class GuiPreferences(NDialog):
         # Text Highlighting
         dialogueStyle   = self.dialogStyle.currentData()
         allowOpenDial   = self.allowOpenDial.isChecked()
-        dialogueLine    = uniqueCompact(self.dialogLine.text())
+        dialogueLine    = processDialogSymbols(self.dialogLine.text())
         narratorBreak   = self.narratorBreak.currentData()
         narratorDialog  = self.narratorDialog.currentData()
         altDialogOpen   = compact(self.altDialogOpen.text())
diff --git a/tests/test_base/test_base_common.py b/tests/test_base/test_base_common.py
index bfd2b55c..006daa42 100644
--- a/tests/test_base/test_base_common.py
+++ b/tests/test_base/test_base_common.py
@@ -37,8 +37,9 @@ from novelwriter.common import (
     formatFileFilter, formatInt, formatTime, formatTimeStamp, formatVersion,
     fuzzyTime, getFileSize, hexToInt, isHandle, isItemClass, isItemLayout,
     isItemType, isListInstance, isTitleTag, jsonEncode, makeFileNameSafe,
-    minmax, numberToRoman, openExternalPath, readTextFile, simplified,
-    transferCase, uniqueCompact, xmlElement, xmlIndent, xmlSubElem, yesNo
+    minmax, numberToRoman, openExternalPath, processDialogSymbols,
+    readTextFile, simplified, transferCase, uniqueCompact, xmlElement,
+    xmlIndent, xmlSubElem, yesNo
 )
 
 from tests.mocked import causeOSError
@@ -377,6 +378,14 @@ def testBaseCommon_uniqueCompact():
     assert uniqueCompact("3 2 1") == "123"
 
 
+@pytest.mark.base
+def testBaseCommon_processDialogSymbols():
+    """Test the processDialogSymbols function."""
+    assert processDialogSymbols("abc") == ""
+    assert processDialogSymbols("\u00ab\u00ab\u00bb\u00bb") == "\u00ab\u00bb"
+    assert processDialogSymbols("-\u2013\u2014\u2015") == "\u2013\u2014\u2015"
+
+
 @pytest.mark.base
 def testBaseCommon_elide():
     """Test the elide function."""