[TYPO3] FE editing: move up/down arrows returns blank page

[Bing Du]

Hi,

Typo3 V4.0.4

Under each content element, I can see a panel that has the following
icons: pencil, move up, move down, hide, new record after and delete.  A
couple of problems and questions.

When I clicked either 'move up' or 'move down' arrow, I got blank window. 
I used 'window' here because there was not only any content, but also no
header, menu, anything.  The URL turned to be
http://www.somesite.edu/index.php?id=2815&TSFE_ADMIN_PANEL%5BDUMMY%5D=432833&TSFE_ADMIN_PANEL%5Bdisplay_top%5D=1&TSFE_ADMIN_PANEL%5Bdisplay_preview%5D=0&TSFE_ADMIN_PANEL%5Bdisplay_cache%5D=0&TSFE_ADMIN_PANEL%5Bdisplay_publish%5D=1&TSFE_ADMIN_PANEL%5Bpublish_levels%5D=0&TSFE_ADMIN_PANEL%5Bpublish_id%5D=2815&TSFE_ADMIN_PANEL%5Bdisplay_edit%5D=1&TSFE_ADMIN_PANEL%5Bedit_displayFieldIcons%5D=0&TSFE_ADMIN_PANEL%5Bedit_displayFieldIcons%5D=1&TSFE_ADMIN_PANEL%5Bedit_displayIcons%5D=0&TSFE_ADMIN_PANEL%5Bedit_displayIcons%5D=1&TSFE_ADMIN_PANEL%5Bedit_editFormsOnPage%5D=0&TSFE_ADMIN_PANEL%5Bedit_editFormsOnPage%5D=1&TSFE_ADMIN_PANEL%5Bedit_editNoPopup%5D=0&TSFE_ADMIN_PANEL%5Bdisplay_tsdebug%5D=0&TSFE_ADMIN_PANEL%5Bdisplay_info%5D=0.
Refreshing the browser doesn't help.

Other icons seem to be working OK.

How to bring back a hidden content element on the frontend?

Thanks in advance for any help,

Bing