DataGrid: Fix focus stuck in grid when first column is fixed and it contains a link (T1216832)

[Alyar666]

See https://devexpress.com/issue=T1216832

[williamvinogradov]

Let's remove the default argument value
Because we don't use this method without passing the value + passing the value is better than the default one defined in the method (more obvious)

Suggested change

	protected _toggleInertAttr(value = false): void {
	protected _toggleInertAttr(value: boolean): void {

[williamvinogradov]

Let's add to the rowsView extender (in them_column_fixing) the method that returns fixed content element.

Something like:

const rowsView = (Base: ModuleType<RowsView>) => class RowsViewFixedColumnsExtender extends baseFixedColumns(Base) {
  // other methods & fields
  public getFixedContentElement(): dxElementWrapper {
    const fixedContentClass = this.addWidgetPrefix(CONTENT_FIXED_CLASS);
    return this.element()?.children(`.${fixedContentClass}`);

And use this method here:

Suggested change

	const $fixedContent = this._rowsView?.element()?.children(`.${this.addWidgetPrefix(CONTENT_FIXED_CLASS)}`);
	const $fixedContent = this._rowsView?.getFixedContentElement();

[williamvinogradov]

Let's remove the eslint-disable-next-line comment and just write the ?? on the next line:

Suggested change

	// eslint-disable-next-line max-len
	this.rowsViewFocusOutHandlerContext = this.rowsViewFocusOutHandlerContext ?? this.rowsViewFocusOutHandler.bind(this);
	this.rowsViewFocusOutHandlerContext = this.rowsViewFocusOutHandlerContext
	?? this.rowsViewFocusOutHandler.bind(this);

[williamvinogradov]

Same comment for the default argument value

[williamvinogradov]

Minor refactoring [OPTIONAL].

Let's make the code more uniform and add the isFirstValidCell variable.
Something like:

const isFirstValidCell = eventArgs.shift && this._isFirstValidCell(this._focusedCellPosition);
const isLastValidCell = !eventArgs.shift && this._isLastValidCell(this._focusedCellPosition);

let isOriginalHandlerRequired = !isCellPositionDefined
      || isFirstValidCell
      || isLastValidCell;

[williamvinogradov]

Let's split this test case into two:

• The first one will check the navigationOfAllCells
• The second one will check the inert attribute

And let's add the third test case like in the original ticket issue:

1. Focus on the last cell (in the DataGrid with fixed columns)
2. Press the Tab
3. Check that DataGrid loses focus or that the element after the DataGrid gains focus

We will check the original issue case with this test case
(In this issue focus goes to the fixed column instead of "move out" from the DataGrid)

[williamvinogradov]

Question:
Why QUnit and not Testcafe? :)