Your comments

Thanks for your assistance Alexander, I appreciate it. It's nice tip, but I would like just make Textastic active without performing any other actions (open dialog, new file or anything else). Is that possible?

Anyway, I can make Textastic active with CMD+TAB, when I use this, Textastic just became active without performing any other action.

OK, I understand. I read your tip from OS X Daily and I try to disable Automatic termination for Textastic exclusively (instead of system wide) with this command modification:

defaults write com.textasticapp.textastic-mac NSDisableAutomaticTermination -bool yes

It works like charm and it don't terminate whole application like maniac every time I close document. Many thanks for this tip!

Sadly, when I hit the Textastic icon in the dock (and application has no window open), it shows me that unnecessarily annoying "open dialog". When I want just make application active, It would be nice make it active and don't perform any useless actions I don't want and I don't care about, just because Apple think it's good for me. But that is an another inconsistent mess Apple bring up with 10.7, and I know, it's "today standard", unfortunatelly.

Thank you for your answer, it's been very helpful. I'm not an developer, I didn't know about that and sorry for my suspicion you don't follow the standards. Unfortunately, Apple start bringing a lot of mess with OS X 10.7 and newer releases, so no surprise for me actually. The result is, that every application handle it different way, so it makes Mac OS behavior less consistent, thats all what Apple has achieved in my opinion. It worked good for years and they just messed it up, sadly (like many other UI-inconsistency things with open/save dialogues and many more I can see at these days). I'm a long time Mac user and I never ever had any problem with application without dialogues, because of menu bar where everybody can see what application is active... but Apple decided to "fix" what don't need to be fixed and bring the mess to the stage. At least that "Automatic termination" can be disable syste-wide and I'll definitely try it.

Just let me know, please, why you decided to use Automatic termination instead of Sudden termination, because Textastic is actually very subtle application, it doesn't consume a lot of system resources. I can understand, when Automatic termination is used for some memory heavy "bloatware", which are typicaly used for an hours and then closed, but I simply can't see any benefits to use it with Textastic.
Textastic isn't just "all-day-long coding" application which I open at the morning and quit at the evening. It's also a handy tool. For example, when I'm opening and closing source files from FTP (for quick editing), I actually open and quit whole Textastic XY times per minute for no actual reason, just because of Automatic termination. I'm not telling it's a big problem when we have a fast SSD's and Textastic starts quickly, but it makes no sense to me.
And one more thing, I know about applications which have an option like "quit application when last window is closed". This is actually why I asked for it in my original post. So how they can handle this, when, If I understand well, you're saying it's impossible use both termination techniques? Maybe it's something like unofficial "hack"?
Many thanks to you again,
Have a nice day,