Optionaltransparenttrue for a transparent background, false for an opaque one.
OptionalwindowTarget window: main or a popup id; omitted or empty, the calling window. There is no fallback to the main window: a caller that is not one of the plugin's windows fails with NOT_FOUND, and a DUI/CUI panel with PANEL_MODE_UNSUPPORTED.
Parameters for
window.setBackgroundTransparency. Set the window WebView background to transparent (revealing backdrop material effects) or opaque. Not supported in panel mode. Fails withOPERATION_FAILED(carrying result fields when the window has a WebView) if neither the window nor the WebView accepted the change.