I try to open two sub vi front panel in third - main vi front panel.

[grzes]

I have two sub vi, and I`d like to see this two vi front panel in main vi front panel window. Does anybody can answer me , If it`s possible?

[Al_S]

Click here for a recent related discussion.
Or have you thought about using a tab control? You can organize controls in pages and have those controls call sub-VIs with or without displaying the front panel of the sub-VI. See the Tab Control Properties.vi example that ships with LabVIEW.
From any LabVIEW window, select Help from the window menubar, then Find Examples >> Search, then enter "tab control" (without the quotes) in the box labeled Type a keyword to find:

[Dennis_Knutson]

A very easy way to do this is to upgrade to LabVIEW 7 and use the new Sub Panel container. There are ways to sort of do it older versions (i.e. child windows) but they all require quite a bit of coding. Just something to think about.