fix(slate): fix insert/remove element edgecase bug in slate (#5926)

packages/volto-slate/news/5928.bugfix

@@ -0,0 +1 @@
+Fix removing an element in slate when cursor is at the end of the element to be removed; Fix losing selection when adding an element. @razvanMiu

packages/volto-slate/src/elementEditor/utils.js

@@ -45,13 +45,16 @@ export const _insertElement = (elementType) => (editor, data) => {
           match: (node) => {
             return Node.string(node).length !== 0;
           },
-        }, //,
+        },
       );
     }
 
     const sel = JSON.parse(JSON.stringify(rangeRef.current));
-    Transforms.select(editor, sel);
-    editor.setSavedSelection(sel);
+
+    setTimeout(() => {
+      Transforms.select(editor, sel);
+      editor.setSavedSelection(sel);
+    });
 
     return true;
   }
@@ -69,10 +72,26 @@ export const _insertElement = (elementType) => (editor, data) => {
  * @returns {Object|null} - current node
  */
 export const _unwrapElement = (elementType) => (editor) => {
-  const [link] = Editor.nodes(editor, {
-    at: editor.selection,
+  const selection = editor.selection || editor.getSavedSelection();
+  let [link] = Editor.nodes(editor, {
+    at: selection,
     match: (node) => node?.type === elementType,
   });
+  const isAtStart =
+    selection.anchor.offset === 0 && selection.focus.offset === 0;
+
+  if (!link && !isAtStart) return false;
+
+  if (!link) {
+    try {
+      link = Editor.previous(editor, {
+        at: selection.anchor.path,
+      });
+    } catch (ex) {
+      link = [];
+    }
+  }
+
   const [, path] = link;
   const [start, end] = Editor.edges(editor, path);
   const range = { anchor: start, focus: end };