QTextEdit cursor position with left/right arrow key

When text is selected from a QTextEdit and pressing left or right arrow key will result wrong cursor position on Mac.

When the left arrow key is pressed the cursor should be positioned at the start of the word. Currently the cursor is positioned one character from the end of the word.

When the right arrow key is pressed the cursor should be positioned at the end of the word. Currently the cursor is positioned one character beyond the word.

The issue is easy to reproduce with the mdi example.