In the variety of reports found in the Historical Data Menu (Historical profit and loss, Historical balance sheet, manual variations) you will find the option "Months reported in budget"

"Months reported in budget" shows which months of your report are "active". The boxes that are checked green (found above each month of your report) are considered active. To make your month "inactive", simply click on the green box to deselect them. Last Month shows the current month that is being used in your historical Profit and Loss Statement, Balance Sheet, etc.

The small green circular icon with the long green tail:

Shows the last month of historical data. In the example below, the current month is March 2020. Therefore, the last month of historical data is February 2020. Everything to the right of it is future projections. 

You can also select all months to be active in one click by selecting the last box to the right.
In this example, the last box is the month of December 2020.

Related Articles (Please refer to the links below)

-How to enter your HISTORICAL DATA Manually?

-How to use the Manual Variations menu?

-Possible Errors in the HISTORICAL DATA Menu