Fix to 'Window Layout' options work properly

[lucydodo]

This patch fixes issue #2434.

QAction* viewMenuPragmas = nullptr;

    // Add entries for toggling the visibility of main tabs
    for (QWidget* widget : {ui->structure, ui->browser, ui->pragmas, ui->query}) {
        QAction* action = ui->viewMenu->addAction(QIcon(":/icons/open_sql"), widget->accessibleName());
        action->setCheckable(true);
        // A few lines below are hidden because they are not needed for the review process.

        if (widget == ui->pragmas)
            viewMenuPragmas = action;
    }

I think it would be good to send the 'QTabWidget::tabCloseRequested' signal to the 'Edit Pragmas' tab for the above code, but after a few days of searching and finding out, I can't seem to do that. Therefore, when QAction is initalized, I modified the code to create and access a pointer variable pointing to QAction for 'Edit Pragmas'.

@mgrojo Please review the code if you possible. Thanks! 😄

[mgrojo]

Awesome! Take a look to these comments before merging.

[lucydodo]

@mgrojo Thanks for the advice and reviews. I just modified and committed it. Since the existing viewMenuParams is a one-time variable, so accessed by findChild when necessary for conserve memory. 😄

[mgrojo]

Perfect. The object name could be useful in the future to manipulate these actions.