Post #527: 
roaoao:
Hi, MatsuikoHiroka.
It’s not easy but possible. Note that render slots are not available by default. You need to render an image or open render result window.
Use this code in Custom tab (Regular Menu):imgs = [img for img in D.images if img.type == 'RENDER_RESULT']; img = imgs and imgs[0]; img and L.context_pointer_set("img", img); img and (lambda img, L: [operator(L, "wm.context_set_int","Slot %d" % (i + 1), 'CHECKBOX_HLT' if img.render_slots.active_index == i else 'CHECKBOX_DEHLT', data_path="img.render_slots.active_index", value=i) for i in range(0, 8)])(img, L)
you are amazing ! its working
thank you very much