Terminal in Web UI: _ show as spaces

[marcoandredinis]

Expected behavior:

Current behavior:
Use the Terminal Web UI and notice that the _ chars appear as spaces

Bug details:

• Teleport version
  master, v13.2.1, v12.4.11 and v11.3.17

• Recreation steps
  Linux w/ Chrome Version 114.0.5735.198 (Official Build) (64-bit)

If you zoom out or zoom in, you'll see the _ (that's how I got the first screenshot)

[zmb3]

For context, this was an issue in the past and we fixed it by upgrading to xterm.js v5 in gravitational/webapps#1400

See also:

• Fonts that print underscore beyond a cell's height don't render anything in the DOM renderer xtermjs/xterm.js#4067
• Text shifted down with some characters truncated on Firefox with xtermjs 4.12.0 xtermjs/xterm.js#3353
• Draw custom underscore glyph if it's determined it would be drawn outside of the cell xtermjs/xterm.js#3423
• Default fonts are vertically offset on some Linux distributions xtermjs/xterm.js#1170
• Tall characters have their top and/or bottom cut off xtermjs/xterm.js#1138

[marcoandredinis]

If we add the xterm-addon-webgl it works:

I've added xterm-addon-webgl and xterm-addon-canvas to have a fallback

[zmb3]

Out of curiosity - do you see the same behavior in Teleport Connect?

[durzo]

This is a pretty frustrating bug that still affects latest versions of Teleport. any progress on this?

[marcoandredinis]

Out of curiosity - do you see the same behavior in Teleport Connect?

No, WebUI master on the left and Connect 14.1.3 on the right

[marcoandredinis]

Fixed in #36763