Fix changing category color in multi playground (#3103)
Fix changing category color in multi playground (#3103)


rachel-fenichel/blockly,mark-friedman/blockly,google/blockly,mark-friedman/blockly,rachel-fenichel/blockly,picklesrus/blockly,mark-friedman/blockly,mark-friedman/blockly,picklesrus/blockly,google/blockly,google/blockly,google/blockly,mark-friedman/blockly,rachel-fenichel/blockly,google/blockly,rachel-fenichel/blockly,rachel-fenichel/blockly,rachel-fenichel/blockly,rachel-fenichel/blockly,google/blockly,google/blockly,mark-friedman/blockly,picklesrus/blockly