perspective cell highlight

packages/web/src/perspectives/PerspectiveCell.svelte

@@ -25,4 +25,8 @@
     border-bottom: 1px solid var(--theme-border);
     border-right: 1px solid var(--theme-border);
   }
+  td:global(.highlight) {
+    border: 3px solid var(--theme-icon-blue);
+    padding: 0px;
+  }
 </style>

packages/web/src/perspectives/PerspectiveHeaderControl.svelte

@@ -179,4 +179,9 @@
   th.columnHeader {
     position: relative;
   }
+
+  th:global(.highlight) {
+    border: 3px solid var(--theme-icon-blue);
+    padding: 0px;
+  }
 </style>

packages/web/src/perspectives/PerspectiveTable.svelte

@@ -154,7 +154,7 @@
     checkLoadAdditionalData();
   }
 
-  function buildMenu({ targetElement }) {
+  function buildMenu({ targetElement, registerCloseHandler }) {
     const res = [];
     const td = targetElement.closest('td') || targetElement.closest('th');
 
@@ -172,6 +172,10 @@
             setConfig,
           })
         );
+      td.classList.add('highlight');
+      registerCloseHandler(() => {
+        td.classList.remove('highlight');
+      });
     }
 
     res.push([