Block doesn't show up in blocks listing Custom block doesn't show up on block listing and pages allowed to display that block.
After switch theme everything is ok, so it is not module layer issue.

I check template.php everything seems to be ok. I check CSS (display: none, etc), it seems that it's not CSS issue.

I asked about other idea's, why that block doesn't show up? I am struggling few hours and starting to have no new idea's to solved that issue
Make sure the region variable is getting printed in page.tpl.php which is associated with your block.
Make sure there is content for your block. If $block['content'] is set to empty in hook_block then the block does not appear at all.
Check block visibility condition as well