SC2Mapster

Is it possible to do next things:
- Change text size of the chat (need lower than current);
- Set chat showcase under dialogs (change dialog layer > 512 - not works);
- Move chat box from center to the left part.

I'm not sure if it can answer all of your question, but this link will atleast tell you how to move the UI around
http://www.sc2mapster.com/forums/resources/tutorials/20323-ui-sc2layout-files-override-method-aiurchef-method/

You could make your own chat system instead of modifying the existing, similar to what is done in Mafia.
Using the above link, you can see how to move the chat frame out of the screen, and then you can make a trigger to listen to the chat message event, and update a label or listbox as chat goes on.
The down side to that is that players wouldn't be able to see whispers, since you moved the chat frame out, and you won't get an event when they receive a whisper.

I know about this link... big prio first 2 strings.

Quote from xxxNEARBYxxx: Go

Is it possible to do next things: - Change text size of the chat (need lower than current);

I have not tested this but I heard that:
you can change the text styles with the .SC2Style files. So you could probably overwrite the current style that the chat uses to change the text size.

Quote from xxxNEARBYxxx: Go

- Set chat showcase under dialogs (change dialog layer > 512 - not works);

I have not tested this but:
you can change the draw layer of the chat box/window to be above/below the dialogs generated by triggers.
<RenderPriority val='###'/> where # is a number.

Quote from xxxNEARBYxxx: Go

- Move chat box from center to the left part.

see the tutorial :)

2Helral "I'll could kiss you" © You give me some hope... but any good tutorial about .SC2Style files?

@xxxNEARBYxxx: Go

only tutorial which concerns sc2styles that I could find.

Ok... got ChatBar.SC2Layout... opened it and.. and too many frame types... for which one i must add render priority to hide sent messages in the game under dialog windows an elements?

<Frame type="ChatRecipientTooltip" name="ChatRecipientTooltipTemplate">
<Frame type="ChatRecipientListBoxItem" name="ChatRecipientListBoxItemTemplate">
<Frame type="ChatRecipientListBoxTooltip" name="ChatRecipientListBoxTooltipTemplate">
<Frame type="Image" name="BackgroundImage">
<Frame type="ChatBar" name="ChatBarTemplate">

@xxxNEARBYxxx: Go

I would say you would need to add it to one of these frame definitions, or both, depending on what you want behind/infront of the dialogs.

Chat display:
<Frame type='MessageDisplay' name='GameUI/UIContainer/FullscreenUpperContainer/ChatDisplay' file='GameUI'>

Chat bar:
<Frame type='ChatBar' name='GameUI/UIContainer/FullscreenUpperContainer/ChatBar' file='GameUI'>