Hi @Sara328 ,
Please try the following methods:
1\ Modify the settings of the screen as follows

2\ Try to drag the form control with the mouse.(Please let me know if you could drag the control)
It can work normally in my environment, please refer to the picture below:

If it still does not work, please try to create a new app and create a new form.
Best Regards,
Wearsky
If my post helps, then please consider Accept it as the solution to help others. Thanks.