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.
with a manual calculation. getBBox() can cause the browser to
re-layout the whole page and we have much of the information
(e.g. individual block height and width) we need already cached.
Note that getBoundingRectangle's calculation is slightly different
than the one returned by getBBox. It is off by 3 in the y direction
due to how one of the curves is drawn. This new calculation is
technically more accurate.
