diff --git a/tp.el b/tp.el
index 22ac59d..74fa8fe 100644
--- a/tp.el
+++ b/tp.el
@@ -1015,11 +1015,20 @@ it will be applied to the text before updating."
                   (save-excursion
                     (tp--replace-reactive-text-in-buffer layer-name new-text props)))))))))))
 
+(defvar tp-preserve-external-properties '(keymap mouse-face cursor pointer help-echo)
+  "List of text properties to preserve during reactive text updates.
+These properties are typically set by external libraries (like twidget's event
+system) and should not be overwritten when tp.el updates reactive text.
+Properties in this list will be preserved from the buffer during updates,
+while other properties will be replaced with the new values.")
+
 (defun tp--replace-reactive-text-in-buffer (layer-name new-text props)
   "Replace text in current buffer for reactive text with LAYER-NAME.
 NEW-TEXT is the new text to replace with.
 PROPS are the properties to apply to the new text.
-Text properties embedded in NEW-TEXT are merged with PROPS."
++Text properties embedded in NEW-TEXT are merged with PROPS.
++Properties listed in `tp-preserve-external-properties' that were applied
++by other libraries are preserved during the update."  
   (goto-char (point-min))
   (let ((match (text-property-search-forward 'tp-name layer-name t))
         ;; Merge embedded text properties from new-text into props
@@ -1027,18 +1036,29 @@ Text properties embedded in NEW-TEXT are merged with PROPS."
     (while match
       (let* ((m-start (prop-match-beginning match))
              (m-end (prop-match-end match))
-             (old-text (buffer-substring-no-properties m-start m-end)))
-        (if (equal old-text (substring-no-properties new-text))
-            ;; Text content is the same, but properties may differ
-            ;; Use set-text-properties to replace with merged properties
-            (set-text-properties m-start m-end merged-props)
-          ;; Text content is different - delete old text and insert new
-          (delete-region m-start m-end)
-          (goto-char m-start)
-          (insert (substring-no-properties new-text))
-          ;; Apply merged properties
-          (let ((new-end (+ m-start (length new-text))))
-            (set-text-properties m-start new-end merged-props))))
+             (old-text (buffer-substring-no-properties m-start m-end))
+             ;; Preserve only specific external properties
+             (existing-props (text-properties-at m-start))
+             (preserved-props nil))
+        ;; Extract only the explicitly listed external properties to preserve
+        (dolist (prop-name tp-preserve-external-properties)
+          (let ((val (plist-get existing-props prop-name)))
+            (when (and val (not (plist-member merged-props prop-name)))
+              (setq preserved-props
+                    (plist-put preserved-props prop-name val)))))
+        ;; Combine merged-props with preserved external props
+        (let ((final-props (append merged-props preserved-props)))
+          (if (equal old-text (substring-no-properties new-text))
+              ;; Text content is the same, but properties may differ
+              ;; Use set-text-properties to replace with final properties
+              (set-text-properties m-start m-end final-props)
+            ;; Text content is different - delete old text and insert new
+            (delete-region m-start m-end)
+            (goto-char m-start)
+            (insert (substring-no-properties new-text))
+            ;; Apply final properties
+            (let ((new-end (+ m-start (length new-text))))
+              (set-text-properties m-start new-end final-props)))))
       ;; Search for next match
       (setq match (text-property-search-forward 'tp-name layer-name t)))))
 
@@ -3008,7 +3028,7 @@ Recursively expands any nested layer names in the returned plist."
   (when-let ((entry (cdr (assoc layer-name tp-layer-alist))))
     ;; Auto-include tp-name for layers with reactive deps
     (let ((needs-tp-name (or include-tp-name
-                              (tp--layer-has-reactive-deps-p layer-name))))
+                             (tp--layer-has-reactive-deps-p layer-name))))
       (cond
        ;; Unified format: entry is (ARGLIST BODY-FORM) where first elem is nil or a list
        ;; Check: exactly 2 elements and first is nil or a list of symbols