Ele - default Popover will be bound to the side of an elemnt. This is what most popovers libraries implement

<div class = "popover" *gistPopover= "'target:ele;'" >

default popover

</div>

On bottom of the element
Mouse Popover will follow the mouse when it is visible and over the parent element

<div class= "popover" *gistPopover= "'target:mouse;'" >

I follow the mouse

</div>

I follow the mouse
X,Y Popover will display at the X,Y coordinates given. X and Y are relative from the top and left visible

<div class= "popover" *gistPopover= "'target:1000,250;'" >

I show at 1000,250

</div>

I show at 1000,250