CTRL+TAB Issue

[Fladknag]

Greetings.
I've looked at the FAQ, done a few searches, experimented with settings etc.
Some specs below.

This is a very basic firefox profile as a first test:
I have {CTRL} bound to mouse 4 - works fine
To cycle through tabs I have {CTRL}{TAB} bound to mouse 5 - does not work, even if i try binding it to mouse 4 instead.
Both binds are set to "Simulated Keys: (pressed)".

The descriptions are really good and it all makes sense... but I can't ctrl+tab.
I must be missing something obvious surely?

Software: v.2.19.2
OS: Windows 10 Pro (new PC, fresh install a few months ago), default English keyboard setting
Mouse: new Asus TUF M5 (basic 5 button mouse)
Driver: TUF GAMING M5 in device manager (21/04/2020)
Note: I uninstalled the ASUS mouse software (armoury crate - it's terrible which is why I searched for an alternative)

Thanks for your time.

[phil]

Odd, just tired it here in Waterfox (based on Firefox code) and its working fine.... (tried on middle button on default profile but the button shouldn't make any difference!)

... OK works fine in Firefox for me too. What have you got set in advanced settings for the "Delay between simulated keys" try increasing it slightly and see if it makes any difference.

Regards,
Phil

[Fladknag]

Thanks. Well this is odd... {CTRL} on mouse 4 is fine but it doesn't work on mouse 5.
{CTRL}{TAB} worked fine for me on middle mouse but not on mouse 4.

... any ideas as to why this would be?

[phil]

That is odd - the button shouldn't matter but I will try it here to be sure. (EDIT: Yeah button 4 and five are find with CTRL TAB for me...)
Do you have any other software that may be interfering I wonder?