Since version 17.2, the initial popup width matches the editor width by default (when PopupWidthMode is set to Default). By setting the WindowsFormsSettings.DefaultSettingsCompatibilityMode global setting to v17_1 or earlier, you can override the default behavior for your version, and enable the popup width to match the content width by default.
Note
The popup width matches the content width by default, regardless of the version of DevExpress components is installed if:
The PopupWidthMode property allows you to override the default behavior for the current editor. Set this property to UseEditorWidth or ContentWidth to enable the initial popup width to match the editor or content width, respectively. See the figures below.
Note
If the editor width is less than the minimum popup width specified with the RepositoryItemPopupBase.PopupFormMinSize setting (or the default minimum popup width), the popup width follows this setting regardless the PopupWidthMode property.