Hi @lipsita ,
Do you want to scroll to top of your Gallery when you click a Icon button?
Based on the needs that you mentioned, I afraid that there is no direct way to achieve your needs. As an alternative solution, I have made a test on my side, please take a try with the following workaround:

Set the OnStart proeprty of the App control or OnVisible property of the first screen of your app to following:
Set(IsReset, true)
Set the Items proeprty of the Gallery to following:
If(
IsReset,
SortByColumns(Filter('20190325_case13', StartsWith(Title, TextSearchBox1.Text)), "Title", If(SortDescending1, Descending, Ascending))
)
On your side, you should type:
If(
IsReset,
'Type your Gallery Items formula here'
)
Set the OnSelect property of the "Up to Top" button to following:
Set(IsReset, false);
Refresh('20190325_case13');
Set(IsReset, true)
On your side, you should type:
Set(IsReset, false);
Refresh('YourDataSource');
Set(IsReset, true)
Please check the following GIF screenshot for more details:
Best regards,