Previously if a workspace.clear() was executed whilst a field was being edited then the following errors would appear in the console and the blockly workspace would become unresponsive.
Uncaught TypeError: Cannot read property 'removeChangeListener' of null(anonymous function) @ blockly_compressed.js:19071Blockly.WidgetDiv.hide @ blockly_compressed.js:20609Blockly.WidgetDiv.hideIfOwner @ blockly_compressed.js:20620Blockly.FieldTextInput.dispose @ blockly_compressed.js:18961Blockly.Input.dispose @ blockly_compressed.js:15786Blockly.Block.dispose @ blockly_compressed.js:17275Blockly.BlockSvg.dispose @ blockly_compressed.js:18327Blockly.Block.dispose @ blockly_compressed.js:17272Blockly.BlockSvg.dispose @ blockly_compressed.js:18327Blockly.Block.dispose @ blockly_compressed.js:17272Blockly.BlockSvg.dispose @ blockly_compressed.js:18327Blockly.Block.dispose @ blockly_compressed.js:17272Blockly.BlockSvg.dispose @ blockly_compressed.js:18327Blockly.Workspace.clear @ blockly_compressed.js:14510window.onmessage @ index.html:175
blockly_compressed.js:19041
Uncaught TypeError: Cannot read property 'scale' of nullBlockly.FieldTextInput.resizeEditor_ @ blockly_compressed.js:19041Blockly.Workspace.fireChangeListener @ blockly_compressed.js:14544Blockly.Events.fireNow_ @ blockly_compressed.js:18833
Explicitly hiding the popup div first avoids this problem.
css to mark text as unselectable instead. I can't prove this is
significantly faster with numbers since the call to setup the time out
costs ~.1ms and the call when the timer fires is ~.05. This happens on almost
every mouse event though. Plus, it seems to remove a flicker of highlighting when
frames are skipped and keeps scrolling via the scrollbar from highlighting.
