Help output: Wanted to close the image pop-up window by pressing any keys

Achievable if you're okay with mucking about in Javascript. I'm assuming you're talking about Frameless output.

Start situation

Confirmation of issue: this image overlay can only be clicked away with the X button.

""Fix""

Add a JS file to your template:

The name of the file does not actually matter, I'm just too lazy to add a new one

(function enableThumbnailCloseOnAnyKey() {
document.addEventListener('keydown', function () {
const thumbnails = document.querySelectorAll('.RH-LAYOUT-thumbnail');
thumbnails.forEach(el => {
el.remove(); // Or use el.style.display = 'none'; to just hide it
});
});
})();

Image overlay should now be cleared on any keypress.

I'm thinking the ESC key would be the best key to suggest Adobe uses.

________________________________________________________

My site www.grainge.org includes many free Authoring and RoboHelp resources that may be of help.

I can't find any way of achieving what you want, any key closing the popup. 

There is a point to make about accessibility. Frameless template as supplied and without customisation meet accessibility requirements, that does not extend to topic content. Adobe have no control over what you do in your topics. It would seem that as designed, you cannot use thumbnails. That said, I think this is something they would consider adding as it would be a good feature.

Please follow this link to report bugs or request new features. https://tracker.adobe.com. Post the link to your bug report / feature request in this thread and others can vote for it. The more people who do so, the higher it gets prioritised. Do submit it as a feature request. Also make it clear whether "any" means any specific key or just any old key.

________________________________________________________

My site www.grainge.org includes many free Authoring and RoboHelp resources that may be of help.

Our requirement is that the Window should also be close if we press any keys from the Keyboard. 

Only Adobe can make that happen so again I have to point you to Support to confirm I am correct, sorry.

Then they or you can request a feature change if they don't have a solution.

________________________________________________________

My site www.grainge.org includes many free Authoring and RoboHelp resources that may be of help.

ALT-F4 doesn't work?