Use gtk3 save as window, instead of the gtk2 one.

Do you want to request a feature or report a bug?
Feature
What is the current behavior?
DesktopEditors uses GTK2 to render the "Save as" window, this cause problems with custom GTK3 themes, also, gtk2 is legacy, with GTK3 being the stable release.
Which versions of DesktopEditors, and which OS are affected by this issue? Did this work in previous versions of DesktopEditors?
4.2.5.312. Arch Linux, updated. I assume it was like this in previous versions of DesktopEditors.
PD: Kickass software, fellows, I replaced Libreoffice with it. Kudos for this Office suite!

[JohnPerkin]

Hello @Ufeldraku!
Thank you for your positive feedback on ONLYOFFICE. We will take this issue into consideration.

[xmbwd]

Can I second this? The current "Save as" or "Open document" windows look like, well, Windows.

[paulocoghi]

This is really important, because it can compromise the first impression for new users.

[paulocoghi]

I believe this issue is solved. Tested on both Ubuntu Mate 18.04 and 20.04 and now the dialogs are using GTK3 or, even if not using, they are following the theme completely.

[keybreak]

on Arch Linux still looks kinda like GTK2 above posted by @xmbwd ☹️
I'd really like more modern dialog too 👍

[XDmitryK]

Native window support was added in version 7.4.0

[Rita-Bubnova]

I close this issue. Feel free to comment or reopen it if you got further questions.