CropUI : Fix cropping of images with default format.
CropUI : Fix cropping of images with default format.

We need the context to be current in order for the default format to be applied appropriately.

hradec/gaffer,johnhaddon/gaffer,johnhaddon/gaffer,ivanimanishi/gaffer,andrewkaufman/gaffer,ImageEngine/gaffer,hradec/gaffer,GafferHQ/gaffer,ImageEngine/gaffer,appleseedhq/gaffer,andrewkaufman/gaffer,GafferHQ/gaffer,lucienfostier/gaffer,andrewkaufman/gaffer,boberfly/gaffer,chippey/gaffer,boberfly/gaffer,appleseedhq/gaffer,hradec/gaffer,ImageEngine/gaffer,chippey/gaffer,GafferHQ/gaffer,lucienfostier/gaffer,chippey/gaffer,johnhaddon/gaffer,johnhaddon/gaffer,hradec/gaffer,ivanimanishi/gaffer,chippey/gaffer,hradec/gaffer,boberfly/gaffer,ivanimanishi/gaffer,johnhaddon/gaffer,ivanimanishi/gaffer,boberfly/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,lucienfostier/gaffer,andrewkaufman/gaffer,appleseedhq/gaffer,ImageEngine/gaffer,GafferHQ/gaffer,appleseedhq/gaffer,lucienfostier/gaffer