Mark internal helpers protected and document HTMLElement cell behaviour

Make createColumnsFromType, setHeaderRow and createPopulatedRow protected
to shrink the public surface, and add @remarks warning that an HTMLElement
cell value must be a unique node per row. Also fix doc typos.

abstract-table.ts

@@ -74,7 +74,7 @@ export abstract class Table<TRow extends object> {
      * e.g. User = { fullname: "Full Name", id: "User ID" }, the columns would be "Full Name" and "User ID" in that order,
      * @return An array of {@link Column} type shape that holds the column info.
      */
-    createColumnsFromType(
+    protected createColumnsFromType(
         exampleObject: TRow, // Needed for runtime, since types don't exist in JS.
         displayNamesAndOrder?: Record<keyof TRow, string>
     ): Column<TRow>[] {
@@ -93,13 +93,13 @@ export abstract class Table<TRow extends object> {
     /**
      * Sets the header cell values on the header row from the {@link columns} on this object.
      */
-    setHeaderRow() {
+    protected setHeaderRow() {
         const thead = document.createElement("thead");
         const headerRow = document.createElement("tr");
 
         for (const column of this.columns) {
             const th = document.createElement("th")
-            th.textContent = column.headerValue; // Header value;
+            th.textContent = column.headerValue; // Column's header text
             headerRow.appendChild(th);
         }
 
@@ -117,6 +117,7 @@ export abstract class Table<TRow extends object> {
     /**
      * Appends one more row to the current rows.
      * @param data Data to append as a row.
+     * @remarks An HTMLElement cell value must be a unique node per row, reusing one HTMLElement instance across rows moves it to the last row only.
      */
     appendRow(data: TRow): void {
         const row = this.createPopulatedRow(data)
@@ -124,8 +125,9 @@ export abstract class Table<TRow extends object> {
     }
 
     /**
-     * Appends multiple rows to the table, at the end off the table.
+     * Appends multiple rows to the table, at the end of the table.
      * @param data The rows to append to the table, in shape of {@link TRow}.
+     * @remarks An HTMLElement cell value must be a unique node per row, reusing one HTMLElement instance across rows moves it to the last row only.
      */
     appendRows(data: TRow[]): void {
         if (data.length === 0) {
@@ -141,8 +143,13 @@ export abstract class Table<TRow extends object> {
      * Creates a row, populated with data, for displaying in the table.
      * @param data The data in the shape of `TRow`, with values populated.
      * @return A HTMLTableRowElement that can then be set on a table.
+     * @remarks If a cell value is an HTMLElement it is appended to the cell. A DOM node can only
+     * exist in one place, so passing the same element instance to multiple rows moves it to the
+     * last row only. Pass a fresh element (or `el.cloneNode(true)`) per row. But keep in mind that
+     * el.cloneNode(true) does not keep event listeners, so if event listeners are used its best
+     * generate any many needed.
      */
-    createPopulatedRow(data: TRow): HTMLTableRowElement {
+    protected createPopulatedRow(data: TRow): HTMLTableRowElement {
         const row = document.createElement("tr");
 
         for (const column of this.columns) {
@@ -196,6 +203,7 @@ export abstract class Table<TRow extends object> {
     /**
      * Deletes all current rows and sets a single row to the data in data param.
      * @param data The data to set the table to. Should be of shape {@link TRow}
+     * @remarks An HTMLElement cell value must be a unique node per row, reusing one HTMLElement instance across rows moves it to the last row only.
      */
     setSingleRow(data: TRow): void {
         this.clearRows()
@@ -205,6 +213,7 @@ export abstract class Table<TRow extends object> {
     /**
      * Deletes all current rows and sets the rows to the data in data param.
      * @param data The data to set the table to. Should be of shape {@link TRow}
+     * @remarks An HTMLElement cell value must be a unique node per row, reusing one HTMLElement instance across rows moves it to the last row only.
      */
     setRows(data: TRow[]): void {
         this.clearRows()
@@ -217,7 +226,7 @@ export abstract class Table<TRow extends object> {
 
     /**
      * Get the message element for the table.
-     * @return The HTMLElement thats used for showing messaged. Or null if its not set. 
+     * @return The HTMLElement thats used for showing messages. Or null if its not set. 
      */
     getMessageElement(): HTMLElement | null {
         return this.messageEl;