Unexpected Connection Behavior Caused by Custom Block Definition

[fu6...@gmail.com]

Hi,

I am currently developing a Scratch-like block-based programming platform, and I have created a custom procedures_defnoreturn block.

When this specific block exists in the workspace, there appears to be an issue with coordinate transformation between a block being dragged from the toolbox and the target block it should connect to. This prevents the expected highlighting from appearing within the required proximity, as demonstrated in the attached video file.

I have been unable to identify the cause of this issue and would appreciate any assistance the community can provide.



Thank you again!

fu6...

[Ben Henning]

Hi,

I'm not sure there's a coordinate issue since the block placed exactly where you dragged it to when you released the mouse. There does seem to be some sort of candidate detection issue happening here that resolves itself after the block is properly placed in the workspace. That surprises me. I'm unfortunately not as familiar with that part of the codebase, and I wonder if this is also related to how these procedure blocks behave. If you're able to create a repro with core Blockly's playground or advanced playground then please do file an issue on the GitHub issue tracker since this may be something the team needs to look into.

Regards,

Ben

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[fu6...@gmail.com]

Hi Ben,

Thank you for your suggestion.

I have made a key discovery: the issue is completely resolved if I disable the Continuous Toolbox plugin. However, the anomaly reappears when the Continuous Toolbox is used in conjunction with a block in the workspace that utilizes my custom class FieldZelosLabelBackground (which inherits from the core class FieldLabelSerializable). As shown in the attached video.

This suggests a potential interaction bug between the Continuous Toolbox's handling of blocks/metrics and custom field serialization/rendering.

Thank you again for your assistance.

fu6...

bhen...@google.com 在 2025年11月12日 星期三凌晨4:32:51 [UTC+8] 的信中寫道：