Dropdown scrolls to selected element (#2897)
Dropdown scrolls to selected element (#2897)

* Dropdown scrolls to selected element

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