Electronic – Eagle 7 two finger scroll issue

In Eagle, the actual final boundaries of the pour are constrained by things in addition to the polygon itself, including the width of the line used to define the polygon and several of the DRC clearance settings. In this case, it sounds like your pour is keeping away from the edges of your board as defined by your dimension lines. You can reduce this clearance in the DRC settings, but I wouldn't recommend reducing it to zero, as this can cause problems in fabricating the board.

Your polygon pour is filling in (showing as blue). To make your "background black" under the transformer, you need to change the shape of your polygon. When you created the polygon, you had to first draw the outline. All you have to do is click the outside edge of the pour and it should highlight the edges of the whole polygon. You can then drag the sides to change its shape.

Not sure why you don't want the pour under the transformer though. Assuming it's insulated with solder mask and your transformer is in a protective case, having the polygon pour completely shouldn't be a problem.