Typically what you want is for backspace to send ^? and not ^H. (I need a citation, but this is typically how modern terminals work.)

It looks like MobaXterm has an option to have backspace send ^H, I imagine that option is currently set on your MobaXterm, perhaps start by trying to uncheck that option.

Then you should look into why Vim has an impression that ^? is not valid for backspace.

Perhaps start by checking what Vim thinks the escape sequences for the backspace key is:

:set t_kb

Normally, this should be ^?, if you have ^H, then check why that might be. Do you have a setting for t_kb in your .vimrc or another sourced file?

If that still doesn't solve it, you might want to explore these tips on backspace problems.

UPDATE: OP tracked it down to the version of xterm they were using. Setting t_kb explicitly in .vimrc produced a successful workaround for the issue.

Quoted by the OP, from the forums of the issue:

Good workaround if you can't/don't want to install a new version of xterm or whatever is to simply go into your .vimrc (in vim) and add the following:

set t_kb=^?

Note that you don't want to type '^' and then '?', but rather hit ; this should create a ^? symbol (or, if you have some similar bug, whatever symbol it thinks is backspace).

Typically what you want is for backspace to send ^? and not ^H. (I need a citation, but this is typically how modern terminals work.)

It looks like MobaXterm has an option to have backspace send ^H, I imagine that option is currently set on your MobaXterm, perhaps start by trying to uncheck that option.

Then you should look into why Vim has an impression that ^? is not valid for backspace.

Perhaps start by checking what Vim thinks the escape sequences for the backspace key is:

:set t_kb

Normally, this should be ^?, if you have ^H, then check why that might be. Do you have a setting for t_kb in your .vimrc or another sourced file?

If that still doesn't solve it, you might want to explore these tips on backspace problems.

UPDATE: OP tracked it down to the version of xterm they were using. Setting t_kb explicitly in .vimrc produced a successful workaround for the issue.

Quoted by the OP, from the forums of the issue:

Good workaround if you can't/don't want to install a new version of xterm or whatever is to simply go into your .vimrc (in vim) and add the following:

set t_kb=^?

Note that you don't want to type '^' and then '?', but rather hit <backspace>; this should create a ^? symbol (or, if you have some similar bug, whatever symbol it thinks is backspace).

Typically what you want is for backspace to send ^? and not ^H. (I need a citation, but this is typically how modern terminals work.)

It looks like MobaXterm has an option to have backspace send ^H, I imagine that option is currently set on your MobaXterm, perhaps start by trying to uncheck that option.

Then you should look into why Vim has an impression that ^? is not valid for backspace.

Perhaps start by checking what Vim thinks the escape sequences for the backspace key is:

:set t_kb

Normally, this should be ^?, if you have ^H, then check why that might be. Do you have a setting for t_kb in your .vimrc or another sourced file?

If that still doesn't solve it, you might want to explore these tips on backspace problems.

Typically what you want is for backspace to send ^? and not ^H. (I need a citation, but this is typically how modern terminals work.)

It looks like MobaXterm has an option to have backspace send ^H, I imagine that option is currently set on your MobaXterm, perhaps start by trying to uncheck that option.

Then you should look into why Vim has an impression that ^? is not valid for backspace.

Perhaps start by checking what Vim thinks the escape sequences for the backspace key is:

:set t_kb

Normally, this should be ^?, if you have ^H, then check why that might be. Do you have a setting for t_kb in your .vimrc or another sourced file?

If that still doesn't solve it, you might want to explore these tips on backspace problems.

UPDATE: OP tracked it down to the version of xterm they were using. Setting t_kb explicitly in .vimrc produced a successful workaround for the issue.

Quoted by the OP, from the forums of the issue:

Good workaround if you can't/don't want to install a new version of xterm or whatever is to simply go into your .vimrc (in vim) and add the following:

set t_kb=^?

Note that you don't want to type '^' and then '?', but rather hit ; this should create a ^? symbol (or, if you have some similar bug, whatever symbol it thinks is backspace).