Problem with editable text fields which update their value when the focus changes

[jteh]

Some web sites use a technique whereby they present the label of an editable text field in its value:

• The value of the field defaults to the label.
• When the field gains focus, the value is cleared.
• When the field loses focus, if the value is empty, it is set back to the label.

The practical upshot is that the field will contain its label if it is empty, but otherwise, it will show the value entered by the user. This is problematic for accessibility anyway, but nevertheless, several sites do this.

Unfortunately, this is particularly problematic for NVDA. NVDA sets the focus to fields as the user moves to them with the cursor keys or quick navigation. The resulting focus event is normally ignored because the virtual caret is already in the field, so NVDA knows that the focus change was caused by the caret movement. However, if a prior element on the page updates during the focus change (as is the case with this technique), the virtual caret will not be in the field because the field wil move in the buffer as a result of the focus change. Thus, NVDA will not ignore the focus event.

This is particularly bad if "Automatic focus mode for focus changes" is enabled because, upon receiving the focus event, NVDA will then activate focus mode, even though the user might have actually moved there using cursor keys or quick navigation.

Steps to Reproduce

1. Ensure that "Automatic focus mode for focus changes" is enabled.
2. Open the attached test case.
3. Ensure you are at the top of the document by pressing ctrl+home.
4. Press e twice to move to the second edit field.

Actual Results

Focus mode will be automatically enabled upon landing in the second edit field.

Expected Results

Focus mode should not be automatically enabled.

Additional Information

• Real world test case

[jteh]

Test case containing two editable text fields with the labels in their values.

[Iris]

To add to this, I've noticed that NVDA, which previously did, no longer work with edit boxes found in IFrames, if that makes sense.

Attached is the log that I got for that particular occurence on Wordpress.com
Iris

****

INFO - nvda (22:29:32):
Starting NVDA
INFO - config.save (22:29:32):
Configuration saved
INFO - core.main (22:29:32):
NVDA version trunk-r2479
INFO - core.main (22:29:32):
Using Windows version (5, 1, 2600, 2, 'Service Pack 3')
INFO - core.main (22:29:32):
Using Python version 2.5.2 (r252:60911, Feb 21 2008, 13:11:45) [MSC v.1310 32 bit (Intel)]
INFO - core.main (22:29:32):
Using comtypes version 0.4.2
INFO - synthDriverHandler.setSynth (22:29:33):
Loaded synthDriver espeak
INFO - core.main (22:29:33):
Using wx version 2.8.7.1 (msw-unicode)
INFO - braille.initialize (22:29:33):
Using liblouis version liblouis-1.3.9, September 17, 2008.
INFO - braille.BrailleHandler?.setDisplayByName (22:29:33):
Loaded braille display driver noBraille
INFO - appModuleHandler.initialize (22:29:33):
loaded default appModule
INFO - appModuleHandler.getAppModuleFromProcessID (22:29:33):
Loaded appModule winamp
INFO - core.main (22:29:33):
NVDA initialized
INFO - appModuleHandler.getAppModuleFromProcessID (22:29:43):
Loaded appModule firefox
INFO - appModuleHandler.getAppModuleFromProcessID (22:31:29):
Loaded appModule nvda
INFO - appModuleHandler.getAppModuleFromProcessID (22:31:38):
Loaded appModule skype
ERROR - queueHandler.flushQueue (22:31:43):
Error in func _queueScriptCallback from eventQueue
Traceback (most recent call last):

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\queueHandler.py", line 53, in flushQueue

func(*args,**kwargs)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\scriptHandler.py", line 74, in _queueScriptCallback

executeScript(script,keyPress)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\scriptHandler.py", line 105, in executeScript

script(keyPress)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\cursorManager.py", line 126, in script_moveByLine_back

self._caretMovementScriptHelper(textHandler.UNIT_LINE,-1)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffers\init.py", line 249, in _caretMovementScriptHelper

super(VirtualBuffer?, self)._caretMovementScriptHelper(*args, **kwargs)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\cursorManager.py", line 63, in _caretMovementScriptHelper

info.expand(unit)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 183, in expand

self._startOffset,self._endOffset=self._getUnitOffsets(unit,self._startOffset)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffers\init.py", line 126, in _getUnitOffsets

return super(VirtualBufferTextInfo?, self)._getUnitOffsets(unit, offset)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 137, in _getUnitOffsets

return offsetsFunc(offset)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffers\init.py", line 91, in _getLineOffsets

return VBufClient_getBufferLineOffsets(self.obj.VBufHandle,offset,config.confvirtualBuffers?maxLineLength?,config.confvirtualBuffers?useScreenLayout?)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffer_lib.py", line 103, in VBufClient_getBufferLineOffsets

dll.VBufClient_getBufferLineOffsets(buf,offset,maxLineLength,cUseScreenLayout,byref(startOffset),byref(endOffset))

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffer_lib.py", line 17, in dllErrorCheck

raise RuntimeError?("error in %s with args of %s"%(func.name,args))

RuntimeError?: error in VBufClient_getBufferLineOffsets with args of (14433536, 1531, 100, 1, <cparam 'P' (02b30fa8)>, <cparam 'P' (02b30b48)>)
ERROR - queueHandler.flushQueue (22:31:44):
Error in func _queueScriptCallback from eventQueue
Traceback (most recent call last):

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\queueHandler.py", line 53, in flushQueue

func(*args,**kwargs)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\scriptHandler.py", line 74, in _queueScriptCallback

executeScript(script,keyPress)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\scriptHandler.py", line 105, in executeScript

script(keyPress)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\cursorManager.py", line 129, in script_moveByLine_forward

self._caretMovementScriptHelper(textHandler.UNIT_LINE,1)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffers\init.py", line 249, in _caretMovementScriptHelper

super(VirtualBuffer?, self)._caretMovementScriptHelper(*args, **kwargs)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\cursorManager.py", line 63, in _caretMovementScriptHelper

info.expand(unit)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 183, in expand

self._startOffset,self._endOffset=self._getUnitOffsets(unit,self._startOffset)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffers\init.py", line 126, in _getUnitOffsets

return super(VirtualBufferTextInfo?, self)._getUnitOffsets(unit, offset)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 137, in _getUnitOffsets

return offsetsFunc(offset)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffers\init.py", line 91, in _getLineOffsets

return VBufClient_getBufferLineOffsets(self.obj.VBufHandle,offset,config.confvirtualBuffers?maxLineLength?,config.confvirtualBuffers?useScreenLayout?)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffer_lib.py", line 103, in VBufClient_getBufferLineOffsets

dll.VBufClient_getBufferLineOffsets(buf,offset,maxLineLength,cUseScreenLayout,byref(startOffset),byref(endOffset))

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffer_lib.py", line 17, in dllErrorCheck

raise RuntimeError?("error in %s with args of %s"%(func.name,args))

RuntimeError?: error in VBufClient_getBufferLineOffsets with args of (14433536, 1531, 100, 1, <cparam 'P' (02b30fa8)>, <cparam 'P' (02b30b48)>)
ERROR - queueHandler.flushQueue (22:31:44):
Error in func _queueScriptCallback from eventQueue
Traceback (most recent call last):

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\queueHandler.py", line 53, in flushQueue

func(*args,**kwargs)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\scriptHandler.py", line 74, in _queueScriptCallback

executeScript(script,keyPress)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\scriptHandler.py", line 105, in executeScript

script(keyPress)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\cursorManager.py", line 129, in script_moveByLine_forward

self._caretMovementScriptHelper(textHandler.UNIT_LINE,1)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffers\init.py", line 249, in _caretMovementScriptHelper

super(VirtualBuffer?, self)._caretMovementScriptHelper(*args, **kwargs)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\cursorManager.py", line 63, in _caretMovementScriptHelper

info.expand(unit)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 183, in expand

self._startOffset,self._endOffset=self._getUnitOffsets(unit,self._startOffset)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffers\init.py", line 126, in _getUnitOffsets

return super(VirtualBufferTextInfo?, self)._getUnitOffsets(unit, offset)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 137, in _getUnitOffsets

return offsetsFunc(offset)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffers\init.py", line 91, in _getLineOffsets

return VBufClient_getBufferLineOffsets(self.obj.VBufHandle,offset,config.confvirtualBuffers?maxLineLength?,config.confvirtualBuffers?useScreenLayout?)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffer_lib.py", line 103, in VBufClient_getBufferLineOffsets

dll.VBufClient_getBufferLineOffsets(buf,offset,maxLineLength,cUseScreenLayout,byref(startOffset),byref(endOffset))

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\virtualBuffer_lib.py", line 17, in dllErrorCheck

raise RuntimeError?("error in %s with args of %s"%(func.name,args))

RuntimeError?: error in VBufClient_getBufferLineOffsets with args of (14433536, 1531, 100, 1, <cparam 'P' (02b30fa8)>, <cparam 'P' (02b30b48)>)
ERROR - queueHandler.flushQueue (22:43:36):
Error in func _queueScriptCallback from eventQueue
Traceback (most recent call last):

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\queueHandler.py", line 53, in flushQueue

func(*args,**kwargs)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\scriptHandler.py", line 74, in _queueScriptCallback

executeScript(script,keyPress)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\scriptHandler.py", line 105, in executeScript

script(keyPress)

File "appModules\_default.py", line 518, in script_review_moveToCaret

info=api.getReviewPosition().obj.makeTextInfo(textHandler.POSITION_CARET)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 710, in makeTextInfo

return self.TextInfo?(self,position)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 155, in init

self._startOffset=self._endOffset=self._getCaretOffset()

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 44, in _getCaretOffset

return self.obj.basicCaretOffset

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\baseObject.py", line 23, in getattr

return getattr(self,'_get_%s'%name)()

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 698, in _get_basicCaretOffset

raise NotImplementedError?

NotImplementedError?
ERROR - queueHandler.flushQueue (22:43:37):
Error in func _queueScriptCallback from eventQueue
Traceback (most recent call last):

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\queueHandler.py", line 53, in flushQueue

func(*args,**kwargs)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\scriptHandler.py", line 74, in _queueScriptCallback

executeScript(script,keyPress)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\scriptHandler.py", line 105, in executeScript

script(keyPress)

File "appModules\_default.py", line 518, in script_review_moveToCaret

info=api.getReviewPosition().obj.makeTextInfo(textHandler.POSITION_CARET)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 710, in makeTextInfo

return self.TextInfo?(self,position)

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 155, in init

self._startOffset=self._endOffset=self._getCaretOffset()

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 44, in _getCaretOffset

return self.obj.basicCaretOffset

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\baseObject.py", line 23, in getattr

return getattr(self,'_get_%s'%name)()

File "C:\Documents and Settings\Iris Pang\My Documents\NVDA\trunk\source\NVDAObjects\init.py", line 698, in _get_basicCaretOffset

raise NotImplementedError?

NotImplementedError?

[jteh]

Replying to Iris:

To add to this, I've noticed that NVDA, which previously did, no longer work with edit boxes found in IFrames, if that makes sense.

It doesn't. :) I think this is a different bug, so please open another ticket and provide exact steps to reproduce. Btw, when including preformatted text like log files, either attach a file or enclose them in {{{ and }}} markers on separate lines.

[jteh]

The solution for this bug is to make sure that the virtual caret is adjusted so that it remains within the node in which it previously resided when an event occurs. This needs to be done in the virtual buffer library. This will probably be done during the refactor.