diff --git a/tagstudio/src/core/library.py b/tagstudio/src/core/library.py
index eae070a7..4a4b70f4 100644
--- a/tagstudio/src/core/library.py
+++ b/tagstudio/src/core/library.py
@@ -341,7 +341,7 @@ class Library:
         #   That filename can then be used to provide quick lookup to image metadata entries in the Library.
         self.filename_to_entry_id_map: dict[Path, int] = {}
         # A list of file extensions to be ignored by TagStudio.
-        self.default_ext_blacklist: list = ["json", "xmp", "aae"]
+        self.default_ext_blacklist: list = [".json", ".xmp", ".aae"]
         self.ignored_extensions: list = self.default_ext_blacklist
 
         # Tags =================================================================
diff --git a/tagstudio/src/qt/modals/file_extension.py b/tagstudio/src/qt/modals/file_extension.py
index f0ce9195..e61368dc 100644
--- a/tagstudio/src/qt/modals/file_extension.py
+++ b/tagstudio/src/qt/modals/file_extension.py
@@ -4,19 +4,34 @@
 
 
 from PySide6.QtCore import Signal, Qt
-from PySide6.QtWidgets import QVBoxLayout, QPushButton, QTableWidget, QTableWidgetItem
+from PySide6.QtWidgets import (
+    QVBoxLayout,
+    QPushButton,
+    QTableWidget,
+    QTableWidgetItem,
+    QStyledItemDelegate,
+    QLineEdit,
+)
 
 from src.core.library import Library
 from src.qt.widgets.panel import PanelWidget
 
 
+class FileExtensionItemDelegate(QStyledItemDelegate):
+    def setModelData(self, editor, model, index):
+        if isinstance(editor, QLineEdit):
+            if editor.text() and not editor.text().startswith("."):
+                editor.setText(f".{editor.text()}")
+        super().setModelData(editor, model, index)
+
+
 class FileExtensionModal(PanelWidget):
     done = Signal()
 
     def __init__(self, library: "Library"):
         super().__init__()
         self.lib = library
-        self.setWindowTitle(f"File Extensions")
+        self.setWindowTitle("File Extensions")
         self.setWindowModality(Qt.WindowModality.ApplicationModal)
         self.setMinimumSize(200, 400)
         self.root_layout = QVBoxLayout(self)
@@ -26,6 +41,7 @@ class FileExtensionModal(PanelWidget):
         self.table.horizontalHeader().setVisible(False)
         self.table.verticalHeader().setVisible(False)
         self.table.horizontalHeader().setStretchLastSection(True)
+        self.table.setItemDelegate(FileExtensionItemDelegate())
 
         self.add_button = QPushButton()
         self.add_button.setText("&Add Extension")