Total Commander

afaik "ctrl+mousewheel" is only used for changing the thumbnail size/zoom mode in thumbnail view.
why not just activate thumbnail mode when using that combination when its not activated.

No, pressing a button or any hotkey its much easier than Ctrl-Mousewheel
which also would start to change the predefined thumbnail saize.

what's easier is debatable. for me it's not for example. my right hand is always on the mouse anyway.

it can be a "[x] activate thumbnail mode on ctrl+mwheel" option.
you can still press "CTRL+SHIFT+F1" or whatever shortcut and then use "ctrl+mwheel". (not really easier)