The default values of the date filter in the Gantt portlet are currently based on today's date. This setup requires manual adjustments when looking at historical data, which can be cumbersome and time-consuming for users.

We propose adding the ability to configure the end of period default value based on the start of period value in the Gantt portlet. For example, if the start of the period is set to two months ago, the end of the period could automatically be set to two weeks after that. This dynamic configuration would enable users to more quickly and intuitively navigate through different date ranges, especially when analyzing historical data.

This feature could include settings that allow users to specify the relative offset between the start and end dates, providing further flexibility in defining date ranges.