Availability of Themes Assembly
This option specifies whether the ASPxThemes assembly is available.
<configuration> ... <devExpress> ... <themes enableThemesAssembly="true" /> ... </devExpress> ... </configuration>
In order to use the DevExpress Web.config section, register this section group beforehand.
This option is useful when you provide a custom appearance by modifying the sources of the default theme files contained within your project’s App_Themes folder (they can be copied there by using the ASPxThemeDeployer tool) without renaming the modified themes. In this case, you should set this option to False to disable using default themes from the ASPxThemes assembly, and avoid overriding your custom theme settings.
The enableThemesAssembly configuration option specifies whether controls should get theme resources from the themes assembly or from the App_Themes folder.
This option is enabled by default.