Toggle Plugin Visibility (Currently Selected/Focused)

That being said,
This script will close a plugin window and open it when it is run again.
If more than one plugin window is open it will close the last focused plugin window each time it is run. When only one plugin remains it will close the last plugin window. After that running the script again will open the last closed plugin window.

sf.ui.proTools.appActivateMainWindow()

// Get open plugin windows
let pluginWindows = sf.ui.proTools.windows.invalidate().allItems.filter(w =>

    (w.title && w.title.value !== null && w.title.value.includes("Plug-in"))
)
let openPluginWindowsCount = pluginWindows.length;

// Store and and close plugin window
if (openPluginWindowsCount > 0) {
    if (openPluginWindowsCount == 1) {
        // Store last open plugin insert slot and track name
        let pluginWindow = sf.ui.proTools.windows.whoseTitle.startsWith("Plug-in: ").first
        const trackName = pluginWindow.popupButtons.whoseTitle.is("Track Selector").first.value.invalidate().value;
        const insertLetter = pluginWindow.popupButtons.whoseTitle.is("Insert Position selector").first.value.invalidate().value;

        globalState.lastOpenPlugin = {
            trackName,
            insertLetter
        }
    }
    // Close plugin window
    pluginWindows[0].windowClose()

} else {
    // Re-open last pluginwindow
    const { trackName, insertLetter } = globalState.lastOpenPlugin;
    const pluginTrack = sf.ui.proTools.trackGetByName({ name: trackName }).track;
    const insertLetters = "abcdefghij";
    const insertNumber = insertLetters.indexOf(insertLetter) + 1;

    pluginTrack.trackInsertToggleShow({
        insertNumber,
    });
}