There are multiple ways to delete a task. Go to the folders tree view and select the folder where the task is located. All the tasks for this folder will be displayed on the list situated on the right side of the folders tree.
Then you can do the following:
1. Right click on the task that you want to delete and choose the Delete option from the displayed popup menu.
or,
2. Click on the task that you want to delete and then click the Delete button on the toolbar (this is the fourth button on the toolbar)
or,
3. Click on the task that you want to delete and then go to File menu and choose the Delete Item option.
or,
4. Click on the task that you want to delete and then go to the Tasks menu and choose the Delete option.
The selected Task will be deleted from the database.