Hi, originally when using photoshop and adding layers on top of a photo I could mark out a shape and paste it straight in and it would fill exactly to the shape, now when I paste inside it only fills areas that are connected to each other? Will attach a picture. It is frustrating as I have to turn off every other layer and picture so there's a plain background to paint inside a shape. how do I fix this?
Thank you in advance!
Ps. more recently my undo button has stopped working! 
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