Auto hides yomichan popups when your mouse leaves the window.

Auto-Hide Yomichan Popups.user.js

// ==UserScript==
// @name         Auto-Hide Yomichan Popups
// @description  Auto-hides yomichan popups after your mouse leaves the window
// @namespace    auto.hide.yomichan.popups
// @version      1.0.0
// @author       You
// @match        https://anacreondjt.gitlab.io/texthooker.html
// @grant        none
// @run-at       document-idle
// ==/UserScript==

//❗ You need to disable the following yomichan setting for this to work.
//Security > "Use a secure container around popups" > turn it off.

//You can add more matched websites above or use your userscript extension to do the same.
//Auto-hide code from: https://github.com/Onurtag/ClipboardInserter_html

//Miliseconds delay to hide the popup after leaving the window
const hideDelay = 1000;

checkMouseInOut();

//Mouse in/out check for yomichan (with shadow dom disabled in settings)
function checkMouseInOut() {
    var theTimer;
    var aFrameWasHidden = false;

    //reset or clear the timer on mouse in/out
    window.onmouseout = resetTimer;
    window.onmouseover = clearTimer;

    function doAction() {
        try {
            //hide yomichan if it exists.
            let yomichanFrames = document.querySelectorAll("iframe.yomichan-popup");
            yomichanFrames.forEach(currFrame => {
                if (currFrame.style.getPropertyValue("visibility") == "visible") {
                    currFrame.style.setProperty("visibility", "hidden", "important");
                    currFrame.classList.add("thisFrameWasHidden");
                    aFrameWasHidden = true;
                }
            });
        } catch (error) {}
    }

    function clearTimer(e) {
        //Mouse entered the window or any element
        clearTimeout(theTimer);
        try {
            if (aFrameWasHidden) {
                let yomichanFrames = document.querySelectorAll("iframe.yomichan-popup");
                yomichanFrames.forEach(currFrame => {
                    if (currFrame.classList.contains("thisFrameWasHidden")) {
                        //transition is used to prevent flashing
                        currFrame.style.setProperty("transition", "visibility 0.5s linear 0.5s");
                        currFrame.style.setProperty("visibility", "visible", "important");
                        setTimeout(() => {
                            currFrame.style.removeProperty("transition");
                        }, 1);
                        currFrame.classList.remove("thisFrameWasHidden");
                        aFrameWasHidden = false;
                    }
                });
            }
        } catch (error) {}
    }

    function resetTimer(e) {
        clearTimeout(theTimer);
        let reltarget = e.relatedTarget || e.toElement;
        if (!reltarget || (reltarget.nodeName == "HTML" && e.target == document.firstChild)) {
            //Mouse left the window here, do action xxxx miliseconds after.
            theTimer = setTimeout(doAction, hideDelay);
        }
    }
}