cursor indent not maintained on a new line

[tonyfast]

Description

consider some indented code \t\tcode. hitting Enter will create a new line and place the cursor at the beginning of the next line. in classic, the cursor would start with the same offset as the prior line (eg \t\t)

Reproduce

1. Type an indented line of code in a notebook code cell.
2. hit Enter
3. the cursor moves to the next line at offset 0

Expected behavior

the cursor should be placed at the beginning of the last indent offset.

Context

• Jupyter Notebook version: <!-- Version: 7.0.0rc0

[tonyfast]

i should probably rename this later to keyboard inconsistencies. i have some other things to tend to, but...

Ctrl+Left can not be used to navigation to the beginning of a line containing an indent. in classic, ctrl+Left would jump words, it would go to beginning of an indent, then visit the prior line. in the currently version, ctrl+left doesn't visit the beginning of the line and goes directly to the preceeding line.

[tonyfast]

can't tab comment blocks or markdown lists with Tab or Shift+Tab

[JasonWeill]

I tried reproducing this behavior in JupyterLab 4 (tip of main) and when I start a code cell with \t\tfoo and press ENTER, line 2 starts with one tab indent (not 2, not 0). Not sure whether this is intended behavior or whether I should start with 2 tabs.

[tonyfast]

i think this was an overall regression in the editor behavior. vscode preserves indents and jupyterlab editors used to, but they don't in v4.

[tonyfast]

it is not possible to type a Tab in an empty string