diff --git a/src/textual/markup.py b/src/textual/markup.py
index 60abb9f5cb..56955c1403 100644
--- a/src/textual/markup.py
+++ b/src/textual/markup.py
@@ -155,7 +155,7 @@ class StyleTokenizer(TokenizerState):
 
 def escape(
     markup: str,
-    _escape: _EscapeSubMethod = re.compile(r"(\\*)(\[[a-z#/@][^[]*?])").sub,
+    _escape: _EscapeSubMethod = re.compile(r"(\\*)(\[[a-z#/@](?:[^[\]]*(?:\[[^[\]]*\])?[^[\]]*)*\])").sub,
 ) -> str:
     """Escapes text so that it won't be interpreted as markup.
 
diff --git a/src/textual/widgets/_select.py b/src/textual/widgets/_select.py
index 568ecd062a..14c45ac6d9 100644
--- a/src/textual/widgets/_select.py
+++ b/src/textual/widgets/_select.py
@@ -253,9 +253,10 @@ def update(self, label: RenderableType | NoSelection) -> None:
         """
         self.label = label
         self.has_value = label is not Select.NULL
-        self.query_one("#label", Static).update(
-            self.placeholder if isinstance(label, NoSelection) else label
-        )
+        if self.is_mounted:
+            self.query_one("#label", Static).update(
+                self.placeholder if isinstance(label, NoSelection) else label
+            )
 
     def compose(self) -> ComposeResult:
         """Compose label and down arrow."""