Calendar in UserForm changing size

Hello all. I have a problem with a calendar. I have added a calendar to UserForm, I sized it nicely to fit the form and added extra contrils to it. But every time I re-open the workbook were this form with a calendar is used, calendar changing it's size, that half of it is outside the form (cropped by form's borders), some controls are covered with a calendar and I cannot see them. I am pretty tired of resizing it back in VBA every time.

Could anybody advise please how can I solve the issue and what could cause this problem.

Thanks in advance.