I found a way to get the result I wanted - but it seems a little bit like a hack to me. What do you think?
Since all controls (=widgets) are stored in a list, you can delete and add items from that list at any position/index of the list.
I did it the following way:
def reset(e):
# remove the Dropdown completly from the GUI
page.remove_at(0) # 0 is the index of the control in the list
# add the Dropdown again at the same position
dropdown = ft.Dropdown(
label = 'Examples',
expand = True,
options = [
ft.DropdownOption(text='Option 1'),
ft.DropdownOption(text='Option 2'),
ft.DropdownOption(text='Option 3'),
]
)
page.insert(0, dropdown)