Hi Ian,
Thanks for reaching out here, and it looks like you're new in the community, so welcome to E-Learning Heroes!
If you're looking to preview a slide and see the realtime updates, I'd recommend using the Preview button in the top ribbon and choosing to just preview that slide. I know that can be difficult if trying to then sync particular elements on the slide with other timeline items such as audio or appearance of objects, and that feedback is something we've shared with our Product development team and our QA team. You're also invited to share feedback with our team using our Feature request form here.
As far as selecting to show/hide more than one item at a time, I am able to click on the "eye" icon and drag up or down to be able to select/unselect more than one at a time. Is that what you meant by continuous click motion?
Additionally if you need any other assistance, we're happy to assist here in the community forums where you'll get help from staff and other community members - but you're also free to reach out to our Support Engineers using this form as they're available 24/7.