Plain text in markdown indents incorrectly

[caneridge]

Issue Type: Bug

When editing a markdown document with these two lines (period denotes a space); tab set to insert 4 spaces:

....a
......b

Selecting lines a,b and pressing tab results in:

........a
........b

Rather than

........a
..........b

The auto indent setting does not change the behavior. I've disabled all of my markdown extensions and the behavior is the same with them or without them. I'd like the ability to have free-format text in markdown that indents by just inserting the indent amount before every line in the selected block.

When indenting this:

           ┌──────┐
           │      │
┌──────────▼────┐ │
│    Block 1    │ │
└───────────────┘ │
        │         │
        │         │
        │         │
        │         │
        ▼         │
┌───────────────┐ │
│    Block 2    │ │
└────────────┬──┘ │
             │    │
             └────┘

It becomes this:

            ┌──────┐
            │      │
    ┌──────────▼────┐ │
    │    Block 1    │ │
    └───────────────┘ │
            │         │
            │         │
            │         │
            │         │
            ▼         │
    ┌───────────────┐ │
    │    Block 2    │ │
    └────────────┬──┘ │
                │    │
                └────┘

VS Code version: Code 1.26.1 (493869e, 2018-08-16T18:31:26.156Z)
OS version: Darwin x64 17.7.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 x 2800)
GPU Status	2d_canvas: enabled checker_imaging: disabled_off flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: enabled rasterization: enabled video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled
Load (avg)	2, 3, 2
Memory (System)	16.00GB (0.60GB free)
Process Argv	/Applications/Visual Studio Code.app/Contents/MacOS/Electron -psn_0_10865244
Screen Reader	no
VM	0%

Extensions (4)

Extension	Author (truncated)	Version
vsc-material-theme	Equ	2.3.0
vscode-docker	Pet	0.1.0
code-spell-checker	str	1.6.10
gitblame	wad	2.4.4

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Build broken on ARM (#11628)
• Cmd+Click (Go to Definition) not working when using require.context (#56006)
• Monolithic structure, multiple project settings (#32693)

[rebornix]

This is due to the limited architecture (regex based indentation rules and only support limited code styles), we may want to consider using formatters if they exist for indenation adjustment (if interested, we can discuss in #19847).

For this particular issue, if the indentation rules are leading to more trouble than having no auto indent, you can set editor.autoIndent to advanced to disable the regex based indentation adjustment or use auto formatting (editor.formatOnType, editor.formatOnPaste). As we don't have an easy good-enough fix for it, we close it for now and explore better solutions through issues like (#19847 and #34621).