Autocomplete box always appears when you backspace even if Autcomplete is Off

[dyavc]

Describe the issue you are having

Even if you turn off Autocomplete in Edit->Preferences, the autocomplete box always appears when you backspace

Did you connect to an already running interpreter or start the interpreter from RIDE?

Start an interpreter

How do you reproduce the issue?

)load dfns ⍝ type the following and then backspace tree

Paste the contents of Help → About (Shift+F1)

IDE:
  Version: 4.4.3726
  Electron: 13.6.9
  Chrome: 91.0.4472.164
  Node: 14.16.0
  Platform: Linux x86_64
  Date: 2022-08-19 13:13:04 +0200
  Git commit: 578d3a5f35111ad0219dfb341e31f0b082544e9e
  Preferences:{
    "kbdLocale":"en_GB",
    "keys":"{\"MA\":[\"Ctrl-F5\"],\"RM\":[\"Ctrl-F6\"],\"PF28\":[],\"PF29\":[],\"PF30\":[],\"PF31\":[],\"PF32\":[]}",
    "zoom":"4",
    "snippetSuggestions":"0",
    "autocompletionDelay":"0",
    "autocompletion":"off"
  }

Interpreter:
  Version: 18.2.46029
  Platform: Linux-64
  Edition: Unicode/64
  Date: Sep 14 2022 at 00:08:21

[dyavc]

I think it must be related to #907