I tried to reduce the total number of elements in the tracker by deleting older entries, but the visibility of some elements did not change.
The next test confirms the dependency on the number of items in a period. I created 25 items with different categories for a single month and everything was ok. When inserting the 26th item the new item was invisible. After deleting another item for that month, the new item now appears.
I think there is a problem showing more than 25 items per month with trackercalendar.
I reported a bug at