Preferences Screen

Select from Menu Edit-Preferences

General tab:

Preferences screen: General

Default Canvas Size - This size will be used for a new project. Usually you don't need to set a bigger values for canvas size. This size is used for preview only. When you export finished mosaic in a file, program will create new empty canvas with the size that you select in Export Image Dialogue and draws mosaic with required resolution.

Clear Recent Files menu - This one will clears Recent Files menu.

Reset Settings to Defaults - This will reset Default Canvas Size to 1800 pixels and Background color to black.

Default Cropping for Layers - This setting affects how the images are placing itself in the layers when dropped or filled from folder. (I don't affect Mazaika's mode)

Always Sort Layers After Rendering - If this check box is checked, the program automatically performs  layer sorting procedure after every completed mosaic rendering.

Do Not Export "Empty" Layers - When this check box is checked the program omits empty layers (i.e. layers without embedded picture) while saving image in file format. For example, if you have collage with 100 layers and only 60 pictures were inserted into this collage, only 60 filled layers will be exported and visible on the output image. 40 empty layers will not be drawn and not be visible at the output file.

Appearance tab:

Preferences screen: Appearance

Here you may select overall program appearance. You need to re-start Mazaika to activate another appearance.
There are three visual styles:

Carbon (It is selected by default):
Interface: Carbon

Interface: Silver

Windows - naive system style. (It depends from installed Windows OS version)
Interface: Windows

Mazaika - (C) 2000-2017 by Boris A. Glazer.