Please fill in this template when reporting a bug, unless you know what you
are doing.
Description of Problem:


Steps to reproduce the problem:
1. start evolution with accessibility enabled.
2. start gnopernicus
3. Compose a HMTL message(with HTML format turned on)
4. Input some words, and make the font to +1.

Actual Results:
the following messages are outputted in console:
** (lt-test_editor:6870): CRITICAL **: file text.c: line 335
(html_a11y_text_get_caret_offset): assertion `p && html_object_is_text(p)'
failed

** (lt-test_editor:6870): CRITICAL **: file text.c: line 527
(html_a11y_text_get_character_count): assertion `to' failed

** (lt-test_editor:6870): CRITICAL **: file text.c: line 422
(html_a11y_text_get_text_at_offset): assertion `to' failed


Expected Results:
When a html object is destroyed, gnopernicus should be notified to destroy
the corresponding a11y object and not to access it any more.

How often does this happen? 
always.

Additional Information: