Click in the menu Layout in submenu Themes on the menu item Manage themes. There is now the choice to modify the currently selected standard theme or use the + button to add a new, custom theme based on the currently used theme. The customizations made on a standard theme as well as the creation and use of a custom theme are kept even on future updates. That can be seen after a theme customization on looking on the folder %APPDATA%\IDMComp\UltraEdit\themes. In this user account related application data folder are stored custom themes or in subfolder overrides the customizations of a standard theme.

The font size of most of the dockable windows can be configured on tab Application by selecting a font and font size for Dockable window font. The font used here is usually a proportional font where each character has its own width. The font and its size for the Output Window can be configured on the tab Output of the Manage Themes dialog window. There is usually used a monospace/fixed width font for the output window like for the document windows showing the contents of the opened files.

The font size used for menus and also the file names of the open files tabs bar and in edit fields like the search combo box are defined by Windows desktop settings. Open on Windows 11 Settings > Accessibility > Text size and change the setting Text size. UltraEdit must be restarted after making a text size change and apply that setting with clicking on the button Apply.

The font and its size for the window Terminal was from UltraEdit/UEStudio v2023.1 to v2024.2 the same as configured for Dockable window font. That is not the case anymore since UltraEdit/UEStudio v2025.0 at least on Windows 11 23H2 and newer Windows 11 versions. I reported this issue by email to UltraEdit support. This issue is still not fixed in currently latest UE/UES 2025.1.0.31. I do not know for sure what does now define he font and the font size for the window Terminal, but it looks like the Windows Text size setting controls also the font size for the window Terminal. That window is a PowerShell window embedded in UltraEdit as dockable window.

There is no font setting in the Manage Themes dialog window for the font and the font size used for the file names on the open file tabs like Edit2 in your screenshot because of that font is defined also by the Windows Text size setting. But there can be added manually to the INI file of UltraEdit two settings to control that font and override the Windows Text size setting for the open file tabs. See my last post at the topic Font size for the File Tabs and the List Views.

The fonts used for the document windows can be configured with the menu items in the submenu Fonts of menu View. There is Set font for normal editing mode which can be also a proportional font as used, for example, by HTML authors. The menu item Set hex / column font opens the dialog window to configure the font for column and hex editing modes. That font must be a fixed width font. If syntax highlighting is configured to use also font styles like bold and italic, the font configured here should be a fixed pitch font where all characters have the same width in all styles.

The Document map window is a graphical representation of the entire file. Click with secondary (right) pointing device (mouse) button into this window displayed on the right side of your screenshot to open its context menu. You can Zoom in and Zoom out, configure in submenu Show what is considered on creation of the document map, and close the document map on not needed at all. It can be opened again by pressing Ctrl+D or by clicking in menu View on the menu item Document map.