I use Google Chrome for a browser. I’m not an expert at Tiddlywiki, I’m just a user of it. I found how to edit a keyboard shortcut in the TW Control Panel. But when I hit CTRL-SH-T for the new key combination for strikethrough, Chrome opens a new browser tab, because the browser intercepts CTRL-T.
I found some pages on Tiddlywiki.com to explain how to do this but I didn’t understand it. I also used Google search and found another page on Tiddlywiki.com and didn’t understand that either. I also searched this forum and it appears using CTRL-SH-T for a new shortcut was not discussed.
If it is really importiant to you, to use a particular shortcut in tiddlywiki, you can look at both the browser and the operating systems shortcut keys to see if you can remove or change the shortcut interfearing with the one you want to use.
Just a little note, if an editor toolbar button is not visible, eg behind more actions, the shortcut will not work. Then if the browser defines that shortcut that will be used. eg h4 behind the more has ctrl-4 which will not work but in FireFox the short cut ctrl-4 opens the 4th browser tab, where ctrl-2 applies h2.