ymf

Could it be because WP is installed in a subdirectory (/wordpress)? Or a conflict between .htaccess files? For some reason I have three of them:

#1. /.htaccess :

# BEGIN WPSuperCache
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
#If you serve pages from behind a proxy you may want to change 'RewriteCond %{HTTPS} on' to something more sensible
RewriteCond %{REQUEST_URI} !^.*[^/]$
RewriteCond %{REQUEST_URI} !^.*//.*$
RewriteCond %{REQUEST_METHOD} !POST
RewriteCond %{QUERY_STRING} !.*=.*
RewriteCond %{HTTP:Cookie} !^.*(comment_author_|wordpress_logged_in|wp-postpass_).*$
RewriteCond %{HTTP:X-Wap-Profile} !^[a-z0-9\"]+ [NC]
RewriteCond %{HTTP:Profile} !^[a-z0-9\"]+ [NC]
RewriteCond %{HTTP_USER_AGENT} !^.*(2.0\ MMP|240x320|400X240|AvantGo|BlackBerry|Blazer|Cellphone|Danger|DoCoMo|Elaine/3.0|EudoraWeb|Googlebot-Mobile|hiptop|IEMobile|KYOCERA/WX310K|LG/U990|MIDP-2.|MMEF20|MOT-V|NetFront|Newt|Nintendo\ Wii|Nitro|Nokia|Opera\ Mini|Palm|PlayStation\ Portable|portalmmm|Proxinet|ProxiNet|SHARP-TQ-GX10|SHG-i900|Small|SonyEricsson|Symbian\ OS|SymbianOS|TS21i-10|UP.Browser|UP.Link|webOS|Windows\ CE|WinWAP|YahooSeeker/M1A1-R2D2|iPhone|iPod|Android|BlackBerry9530|LG-TU915\ Obigo|LGE\ VX|webOS|Nokia5800).* [NC]
RewriteCond %{HTTP_user_agent} !^(w3c\ |w3c-|acs-|alav|alca|amoi|audi|avan|benq|bird|blac|blaz|brew|cell|cldc|cmd-|dang|doco|eric|hipt|htc_|inno|ipaq|ipod|jigs|kddi|keji|leno|lg-c|lg-d|lg-g|lge-|lg/u|maui|maxo|midp|mits|mmef|mobi|mot-|moto|mwbp|nec-|newt|noki|palm|pana|pant|phil|play|port|prox|qwap|sage|sams|sany|sch-|sec-|send|seri|sgh-|shar|sie-|siem|smal|smar|sony|sph-|symb|t-mo|teli|tim-|tosh|tsm-|upg1|upsi|vk-v|voda|wap-|wapa|wapi|wapp|wapr|webc|winw|winw|xda\ |xda-).* [NC]
RewriteCond %{HTTP:Accept-Encoding} gzip
RewriteCond %{HTTPS} on
RewriteCond %{DOCUMENT_ROOT}/wordpress/wp-content/cache/supercache/%{HTTP_HOST}/$1/index-https.html.gz -f
RewriteRule ^(.*) "/wordpress/wp-content/cache/supercache/%{HTTP_HOST}/$1/index-https.html.gz" [L]
</IfModule>
# END WPSuperCache

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

#2. /wordpress/.htaccess :

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /wordpress/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /wordpress/index.php [L]
</IfModule>
# END WordPress

#3. /wordpress/wp-content/cache/.htaccess :

# BEGIN supercache
<IfModule mod_mime.c>
  <FilesMatch "\.html\.gz$">
    ForceType text/html
    FileETag None
  </FilesMatch>
  AddEncoding gzip .gz
  AddType text/html .gz
</IfModule>
<IfModule mod_deflate.c>
  SetEnvIfNoCase Request_URI \.gz$ no-gzip
</IfModule>
<IfModule mod_headers.c>
  Header set Vary "Accept-Encoding, Cookie"
  Header set Cache-Control 'max-age=3, must-revalidate'
</IfModule>
<IfModule mod_expires.c>
  ExpiresActive On
  ExpiresByType text/html A3
</IfModule>
# END supercache

Yes, I figured that out.

A related issue is: in Google Chrome browser, the right-floated Addthis toolbar sometimes splits in two lines (as shown here: http://img832.imageshack.us/img832/6755/unled1tx.gif). The workaround is to manually define the toolbar’s width, e.g.

.addthis_toolbox {display: inline; float: right; min-width: 163px;}

Update: Apparently, they at webhostingpad.com do not implement fixes system-wide, but rather at individual servers. After they migrated my account to a different server, the problem reappeared. To their credit, they quickly applied the fix to that new server after I asked them.