Description of the problem:
In Unix-like systems is easy to manage files tarball (tar.gz, tar.xz, tar.bz2, etc.) in the sense that these are recognized so that are compressed and decompressed transparently with a single action. This is in contrast to the handling of these files in Windows systems, in which you must first create a *.tar and then compress it (just to decompress).
I see this as a problem, especially for interoperability between systems, as it is a bit annoying to have to perform two actions (and waiting involved) to compress or decompress a file.
Windows 7 SP1 x32
how to reproduce:
Select a folder - context menu / add file
Select File Format "tar" (wait for file creation)
Select the newly created tar file - context menu / add file
Select compression method (wait for file creation)
To decompress: decompress first file and then extract the tar file (two steps)
Compress / decompress files using the context menu with a single step
Apparently, 7-zip does not recognize the suffixes short equivalents for tarball (taz, txz, tgz, tbz, etc)