I just upgraded from ver. 2.6.3 to 2.8.2 and I can no longer activate themes. The dashboard indicates the theme I selected is active but I cannot preview it nor can I see it in the browser. I also may need to set permissions and I'm not sure how to do that or if I need to. But I'm noticing any tweeks I try to make are ignored. I appreciate any help you can provide as I'm very new to this. Thank you!