Before 2 weeks when the teachers try to add new activity the html Editore cant display coorectly, can anyone help to resolve this errors
Check to see what browser they are using and if they are opening their browser to full size.
Most likely this is a custom theme css issue - either your custom theme css files override or change some css of standard theme or some 3rd party activity css (for example in mod/customactivity/styles.php) might have some css that overrides previously defined css.
Default width of editor (htmlarea) can be defined in core code of moodle and separately in activities but there is no such option available for teachers or in administration menu and usually there is no need to edit core files to change editor width.
You could debug css with some firefox plugin like Web Developer or Firebug to find the reason from custom theme css. If the same thing happens with standard theme as well check next 3rd party activity css (modules ancd blocks).
Finally I trace the moodle and I found conflict between three blocks
After I uninstall it the editor width is okay
Thanks again for replay