The behavior of paging is inconsistent when filter or sub-filter is used.

1. Go to Configuration -> Hosts -> Items list;
2. make sure you have enough records that the is paging visible;
3. go to page, for example, 5;
4. type something in the filter (or press sub-filter value) and apply the changes;
5. observe user is now back in page 1.

This, in my opinion, is correct. We have new and different information to show. It's OK to be in page 1 after filter or sub-filter is changed.

But now let's see another filter.
1. Go to, for example, Monitoring -> Hosts (other filters like Monitoring -> Problems work the same. And after ZBXNEXT-6687 this will also affect Latest data)
2. make sure you have enough records that the is paging visible;
3. go to page, for example, 5;
4. type something in the filter and apply the changes;
5. depending on the results you can be, for example, in page 5 if there are enough records, meaning the page number is remembered or you can be in page 3 if there are not enough records for five pages;
6. Now change filter again so that there are enough records and observe you again are in page 5. The page in being remembered.

If the filter is changed, I think we should reset the page to 1, otherwise user can be in some random page after filter is applied. And it's inconsistent with item list paging behavior. Both should work the same. Either we always remember the page or always forget and reset to page 1.