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Description

The new focus changes in v12.1.0 have broken backwards compatiblity for other plugins specifically this PR #9082

This ended up causing the Toolbox Search plugin to break in v12.1.0 which was originally still working in v12.0.0 google/blockly-samples#2577

You can see the broken feature here https://google.github.io/blockly-samples/plugins/toolbox-search/test/index.html the custom input box in the toolbox category can never be focused.

We have been discussing if this backwards compatibility should be fixed or the new focus manager changes should be used in this case going forward.

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