To turn off filtering, click on the button 
.
Excel-like filtering
JExcel enables you to sort and filter your issues without JQL knowledge, like in Excel!
The very first step of sorting and filtering issues is to make sure to enable Filter row 
on the upper right panel.
If it is enabled, the filter option is visible below each column title.
JExcel supports filtering methods like
Text filter
Checkbox
Calendar
What is Fast filtering?
A brand new and extremely fast data filtering method. Hold Alt and click left mouse button in a cell to easily filter by its data.
To turn off filtering, click on the button .
JExcel enables you to filter your issues without JQL knowledge, like in Excel!