Accessibility: the selection state of components is not reported during the "custom" installation process

As a user of VoiceOver screen reader on Mac OS, I am currently not able to perform custom installations because the selection state of the components is not reported to the or by the screen reader.

Steps to reproduce:

1. Download the QT installer.
2. Launch VoiceOver screen reader by pressing Command+F5 or asking Siri to "start VoiceOver".
3. Proceed through the installation process and choose "custom" on the "installation type" screen. Click "next" to proceed.
4. On the next screen tap to the "components" tree, arrow up and down through the options, press left / right arrows to expand and collapse (if necessary), then press space bar on the components you want to select.
5. Observe spoken feedback and focus behavior.

Observed results:

1. VoiceOver is not aware of the selection state of the item, thus making it really difficult to select more than one component.
2. If I select a component with a space bar, the focus jumps to the "next" button.

Expected results:

1. As VoiceOver user, I should be able to hear when a component is selected as well as which ones are already selected when arrowing through the tree.
2. The focus should not jump to the "next" button automatically before the user is finished with their selection.