scratchfoundation / scratchfoundation/scratch-blocks

The editor runs slowly when dragging the whole workspace

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#2,675 0 comments 0 reactions 0 assignees View on GitHub

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Low Prevalence Medium Severity priority 4
Dominant language
JavaScript
Stars
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Forks
1.6k
Avg merge
4h 51m
Merged PRs (30d)
12

Description

When dragging the background (or dragging the scrollbar) with lots of blocks, it seems running very slowly compared to simply using the mouse wheel. On my computer, I can feel that situation obviously in about 1k blocks in Google Chrome. In my view, dragging the whole workspace should be as fast as using the mouse wheel.

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the slowdown in Google Chrome with about 1,000 blocks, comparing dragging the background or scrollbar with the mouse wheel. Trace the workspace interaction and rendering path to identify why dragging is slower. Done means whole-workspace dragging feels comparable to mouse-wheel scrolling at that scale.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript
Domain
frontend, performance
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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