It's a suggestion about tag(Ctrl+t)

[ammero]

I mainly used acdsee, but I started writing xnview again, and I think it's much more convenient and better than before.
It's a good viewer and it's improved a lot, but I'm a photographer and I'm using a lot of the tag function (photo selection function) of photos.
It's convenient to press "\" to select a photo
In xnview, you have to press "Ctrl+t", but when I choose hundreds of pictures, my hand hurts so much and it's so hard because there's no shortcut change function, but I hope you can make it a little more convenient.
And I'd also like to have the option to collect and choose only the teg photos.
It's a function that does everything in acdsee, but if it weren't for this function, I wouldn't have used the acdsee program, but I think it would be good to add more function to select pictures.
And the photo comparison function is also the best program among viewer programs even if it only has a zoom function when comparing two and several pictures like Lightroom.
The photo editing function can be used in various programs, and professional work uses other programs, and it would be great if there was a good function to classify and compare photos as a viewer.

[jkm]

Welcome to the forums...

Some parts of what you write are not understandable, so you may need to try again to write more clearly. It makes it hard for others to respond.

If your "hand hurts so much" then see a doctor. But for how to use the software, I will try and help you...

It's convenient to press "\" to select a photo
In xnview, you have to press "Ctrl+t", but when I choose hundreds of pictures, my hand hurts so much and it's so hard because there's no shortcut change function

You are mistaken here. The shortcuts CAN be changed. Please go to Tools->Settings:Interface:Shortcuts
There you will find a list of keyboard shortcuts triggering Actions/Commands in the browser. All those shortcuts can be changed
Find the Action you are interested in (by default "Tag/Untag current" is Ctrl-T), highlight it with the mouse, select the CUSTOM option at the bottom of the dialog, click in the shortcut box where it shows the key sequence and it will highlight in blue, and then hit the keystroke or keystroke combination you want to use. Then change another if you want, and when done click OK. It's that simple. Please try it.

And I'd also like to have the option to collect and choose only the teg photos.
It's a function that does everything in acdsee, but if it weren't for this function, I wouldn't have used the acdsee program, but I think it would be good to add more function to select pictures.

I have no idea what this is supposed to mean. There's no "function that does everything". If you mean "select all the tagged files" then there is an Action for this too. Find "Select tagged files" in the dialog I mentioned above, and assign a shortcut key to it, whatever keystroke you want. If you mean tag all visible files, then just select all with Ctrl-A, then hit your new tag shortcut. Two keystrokes and it's done.

Up at the top of that dialog a little menu, that by default says Browser. This lets you select Actions available in the Browser, or in the Viewer.
If you want to change or assign shortcut keys available in the viewer, do it here. Next to that is a filter box. Type a word in it, like tag, and it will show you all the Actions that have the word tag in them. Maybe you will see other actions you like. There are actions to invert tag status, clear all tagged files, etc. You can assign keyboard shortcuts to them.

Hopefully this helps. Good luck.