diff --git a/novelwriter/core/index.py b/novelwriter/core/index.py
index 119b4416..6a90c5f0 100644
--- a/novelwriter/core/index.py
+++ b/novelwriter/core/index.py
@@ -551,7 +551,7 @@ class NWIndex:
         return 0
 
     def getTableOfContents(
-        self, rHandle: str, maxDepth: int, skipExcl: bool = True
+        self, rHandle: str | None, maxDepth: int, skipExcl: bool = True
     ) -> list[tuple[str, int, str, int]]:
         """Generate a table of contents up to a maximum depth."""
         tOrder = []
diff --git a/novelwriter/dialogs/about.py b/novelwriter/dialogs/about.py
index 09eab5b0..f22a8238 100644
--- a/novelwriter/dialogs/about.py
+++ b/novelwriter/dialogs/about.py
@@ -139,6 +139,7 @@ class GuiAbout(QDialog):
     def _doClose(self) -> None:
         """Close the dialog"""
         self.close()
+        self.deleteLater()
         return
 
     ##
diff --git a/novelwriter/dialogs/projdetails.py b/novelwriter/dialogs/projdetails.py
index 40a70b71..272a20a4 100644
--- a/novelwriter/dialogs/projdetails.py
+++ b/novelwriter/dialogs/projdetails.py
@@ -98,6 +98,7 @@ class GuiProjectDetails(NPagedDialog):
         """Save settings and close the dialog."""
         self._saveGuiSettings()
         self.close()
+        self.deleteLater()
         return
 
     ##
@@ -428,7 +429,7 @@ class GuiProjectDetailsContents(QWidget):
     #  Internal Functions
     ##
 
-    def _prepareData(self, rootHandle: str) -> None:
+    def _prepareData(self, rootHandle: str | None) -> None:
         """Extract the information from the project index."""
         logger.debug("Populating ToC from handle '%s'", rootHandle)
         self._theToC = SHARED.project.index.getTableOfContents(rootHandle, 2)