From 881ff55d5477b60459488921b2f5a6c32f1f95de Mon Sep 17 00:00:00 2001
From: Parthib Roy <159463257+proy30@users.noreply.github.com>
Date: Fri, 3 Jan 2025 14:48:16 -0800
Subject: [PATCH] fix lattice validation (#776)

---
 .../dashboard/Input/latticeConfiguration/latticeMain.py    | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/python/impactx/dashboard/Input/latticeConfiguration/latticeMain.py b/src/python/impactx/dashboard/Input/latticeConfiguration/latticeMain.py
index 5371042c2..c3d16e740 100644
--- a/src/python/impactx/dashboard/Input/latticeConfiguration/latticeMain.py
+++ b/src/python/impactx/dashboard/Input/latticeConfiguration/latticeMain.py
@@ -156,7 +156,12 @@ def on_lattice_element_name_change(selectedLattice, **kwargs):
 @ctrl.add("add_latticeElement")
 def on_add_lattice_element_click():
     selectedLattice = state.selectedLattice
-    if selectedLattice:
+
+    if selectedLattice not in state.listOfLatticeElements:
+        state.isSelectedLatticeListEmpty = (
+            f"Lattice element '{selectedLattice}' does not exist."
+        )
+    else:
         add_lattice_element()
         state.dirty("selectedLatticeList")