See above

Assuming some Player (application) is using Ctrl+WheelUp and Ctrl+WheelDown to set its volume.

You will set 7+TT that whenever you WheelUp on a thumbnail, it will send a Ctrl+WheelUp message to app, and whenever you WheelDown on a thumbnail, it will send a Ctrl+WheelDown message to app.

You are right, it will require to specify the app, because you don't want those messages to be sent in other apps thumbnails.

I don't know if thumbnails are supported yet in Advanced Options of 7+TT.

But it if does, I think your request may be possible (with efforts) by a combination of 7+TT with hotkeyP by using this:

https://tweaker.userecho.com/communities/1/topics/287-ability-to-run-application-or-even-better-trigger-a-media-button-on-clicking-on-empty-taskbar-space

@RaMMicHaeL, Adding "Send keys to window" feature to 7+TT?

Another idea can be "Send to Taskbar Inspector":

when there is Mouse click event on a taskbaritem, Takbar Inspector will open, and the buttons that will be sent to Taskbar Inspector, will be selected in Takbar Inspector.

Then the user will be able to use the Taskbar Inspector Context Menu, to Cascade / Tile etc the selected buttons/windows.

ctrl+click is an example of course. (the way it worked in XP)

"Select" should be added to:

Advanced options ›› Mouse Button Control

If the problem was the selected buttons color,
you can also use a check box icon

in the same way you use with 7-Taskbar-Numberer.

to add / remove this icon by ctrl+click

It's already suggested...

I think it would be better to add such features to Advanced optioins, for both Mouse and Keyboard shortcuts.

There are programs that also letting you do such things by actions on Window Items. For Example:

Direct Folders lets you to Right Click on Close button (X button of a window)  to make a window "Always on Top".

I guess you mean Advanced Options.

Right Click on system tray icon

You may read help file.

OptionsEx

w10_large_icons

When using large icons, their size was 32x32 on earlier Windows versions. On Windows 10, the default size is 24x24. This option allows to have 32x32 sized icons again.

0 - Disabled (default)

1 - Enabled

but one of the tweaker's principles is that it doesn't write to the registry and doesn't modify system files. Basically, no permanent changes to the system.

This sounds like the definition of portable version...

There are many registry tweaks, and implementing them all in such a way that the registry is not actually modified is possible, but not likely to happen.

I can understand that. Therefore I wrote: "Maybe the main functions/functionality should be taken into account here."

For example, I agree that "Adjust Taskbar Thumbnail Delay Time" feature is a minor registry tweak relatively to "Show Labels" feature, which its lack in portable version is changing the whole workspace experience, IMHO.

On the other hand, you can implement it yourself by modifying the registry on the target machine, and reverting the changes when done. With a bit of work it can also be automated.

In my case it was a library PC, and I'm afraid to do such things on not my PC.

If you're using Windows 10

Windows 7 :)

I don't know if to open a new "Idea" for each topic. Anyway,

1. This is the source:

http://www.askvg.com/how-to-adjust-taskbar-thumbnail-delay-time-in-windows-7/

2. If I remember correctly, I think you once wrote you don't want to add in 7TT things that can be done via Registry and Properties. That's ok till you realize that it can make problems in portable...

Maybe the main functions/functionality should be taken into account here.

3. On the other hand, the current behavior is not logical if that option disabled...

I think I found a trick how to make the implementation really easy.

What do you say about Hide and Unhide all windows as solution?

Try
Advanced Options > OptionsEx
show_desktop_button_size = 1