Editor to become unresponsive when both Overtype and Highlight Matching Tag extensions are enabled

[rbolsius]

Type: Bug

When the Highlight Matching Tag extension and the Overtype extensions are both enabled, VS Code becomes unresponsive to keypresses when inserting new text into medium to large XML files. Delays when typing begin to be observable even with XML files 256KB in size, and editing XML files 1MB or 2MB in size is impossible. Some keyboard actions like backspace and delete are still responsive, but typing any new characters results in nothing being inserted.

In the developer tools console there are many messages like the following.

INFO UNRESPONSIVE extension host: starting to profile NOW

When either one of these extensions is enabled by itself, VS code responds immediately to keystrokes when editing larger XML files. However, when just these two extensions are enabled, even XML files around 256KB begin to show significant delays when typing.

Extension version: 0.5.0
VS Code version: Code 1.77.1 (b7886d7461186a5eac768481578c1d7ca80e2d21, 2023-04-04T23:21:11.906Z)
OS version: Windows_NT x64 10.0.19045
Modes:
Sandboxed: No

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz (8 x 2592)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: disabled_off direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_renderer: enabled_on video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: disabled_off
Load (avg)	undefined
Memory (System)	15.83GB (3.92GB free)
Process Argv
Screen Reader	no
VM	0%

[rbolsius]

Since it is not clear which extension is at fault, I have also created the following issue against the Highlight Matching Tag extension.

vincaslt/vscode-highlight-matching-tag#145

[rbolsius]

This issue seems very similar to #34, although that was reported when Overtype is used together with the Better Folding extension.

[gmccullo]

I'm also seeing performance problems on bigger (markdown) files, but not only with some other specific extension. Maybe it's just conflicting with any other extension that also does things in the editor? My suspicion is that this may be a function of how extensions interact with the editor. So when you have multiple extensions and/or long files you start to see this lag behavior.