MdiArea in centralWidget -> many mdiSubwindows resize MainWindow

[HappyCoder]

Hello,

i have in my centralWidget a QMdiArea. When i open many files (30) i got in
Window mode many windows, thats ok.
When i now switch from "cascade" to "tile" the mainwindow resizes and is
much bigger than my screen.

How can i prevent a resize of the mainwindow if i activate "tile" view of
many windows in a mdiAdea?

i tried this, but didn't work:

void MainWindow::resizeEvent(QResizeEvent *event)
{
    ui->centralWidget->setMaximumHeight(geometry().height());
    ui->centralWidget->setMaximumWidth(geometry().width());
}

void MainWindow::resizeEvent(QResizeEvent *event)
{
    ui->centralWidget->setMaximumHeight(geometry().height());
    ui->centralWidget->setMaximumWidth(geometry().width());
}

To copy to clipboard, switch view to plain text mode 

Thx