After some search in this forum I get to the conclusion that my issue might be a new one.
I did a vocabulary trainer with an ui.view to display labels and buttons of some kind.
One of these buttons calls an ui.list_dialog, where I can choose from a list of strings. The dialogue used to block the underlying view, so I could retrieve the selected string in the following line of code.
After updating my IPhone to IOS15.2.1 this is no longer true.
This is a very short code to demonstrate my problem
```

coding: utf-8

import dialogs
import ui

class my_view(ui.View):

def __init__(self):
    self.background_color='#ffffff'
    btn = ui.Button(title='Okay',action=self.action)
    self.add_subview(btn)
    self.lbl=ui.Label(text='None')
    self.lbl.y=btn.y+20
    self.add_subview(self.lbl)

def action(self,sender):
    act=dialogs.list_dialog('select',['A','B'])
    #next line is executing before dialogue closed
             self.lbl.text= act

if name == 'main':
v = my_view()
v.present('full_screen') ```

@WilliD55 Not sure it is relative but the line "self.lbl.text= act" is not correctly indented

Anyway, I don't have any problem on my IPad iOS 15.2.1

If you have the problem try

    @ui.in_background
    def action(self,sender):

@cvp : this line did the change with the example code as well as with my application.
Thanks a lot

@WilliD55 You're welcome in this forum