Unsolved Problem on list of checkbox signals

[Moeka_Chan]

Hi,
I created a list of checkboxes.
The top one is for users to select/deselect all.
When an instance is checked, it will be shown in the GUI.

I use Qtstandarditemmodel for the checkboxes and itemChanged for signals.
When 'all' is checked, it makes others checked by a loop.
The problem is that all the instances are shown in GUI one after another.
I want to make all the instances shown at the same time.

The reason for showing one after another:

When any single instance is check, it sends a signal to show the checked instance.
However, when 'all' is checked, it checks all the instances one by one. When each instance is checked, this is like running the sentence above one by one. Thus, all the instances are not shown at the same time.