nsIWindowCreator
embedding/base/nsiwindowcreator.idlscriptable a callback interface used by gecko to create new browser windows.

Embedded Dialog API
an embedding application must implement the nsiwindowcreator nsiwindowcreator interface and hand off a reference to the implementation to the windowcreator service during application initialization.
...gecko uses nsiwindowcreator to create all new windows for which no explicit override (the advanced api) has been given, and for browser windows in general.
... the precise appearance and contents of the new window are defined by the application, though the app should conform to the chromeflags parameter of nsiwindowcreator::createchromewindow.

Embedding Mozilla in a Java Application using JavaXPCOM - Archive of obsolete content
for example: mozilla mozilla = mozilla.getinstance(); windowcreator creator = new windowcreator(); // implements nsiwindowcreator nsiservicemanager servicemanager = mozilla.getservicemanager(); nsiwindowwatcher windowwatcher = (nsiwindowwatcher) servicemanager .getservicebycontractid(ns_windowwatcher_contractid, nsiwindowwatcher.ns_iwindowwatcher_iid); windowwatcher.setwindowcreator(creator); in this example, we have a java class called windowcreator, which implements the nsiwindowcreator interface, and we wa...
... instance of the xpcom service manager nsiservicemanager servicemanager = moz.getservicemanager(); // now we need to get the @mozilla.org/toolkit/app-startup;1 service: nsiappstartup appstartup = (nsiappstartup)servicemanager.getservicebycontractid("@mozilla.org/toolkit/app-startup;1", nsiappstartup.ns_iappstartup_iid); // get the nsiwindowwatcher interface to the above nsiwindowcreator windowcreator = (nsiwindowcreator)appstartup.queryinterface(nsiwindowcreator.ns_iwindowcreator_iid); // get the window watcher service nsiwindowwatcher windowwatcher = (nsiwindowwatcher)servicemanager.getservicebycontractid("@mozilla.org/embedcomp/window-watcher;1", nsiwindowwatcher.ns_iwindowwatcher_iid); // set the window creator (from step 6) windowwatcher.setwindowcreato...

Embedding Tips
implement and register a nsiwindowcreator object with the window watcher service.
... the nsiwindowcreator::createchromewindow method will be called whenever gecko needs to open a new window.

nsIWebBrowserChrome
chrome_with_size 4096 specifically for use with nsiwindowcreator.
... chrome_with_position 8192 specifically for use with nsiwindowcreator.

nsIWindowWatcher
window aparent); nsidomwindow getwindowbyname(in wstring atargetname, in nsidomwindow acurrentwindow); nsisimpleenumerator getwindowenumerator(); nsidomwindow openwindow(in nsidomwindow aparent, in string aurl, in string aname, in string afeatures, in nsisupports aarguments); void registernotification(in nsiobserver aobserver); void setwindowcreator(in nsiwindowcreator creator); void unregisternotification(in nsiobserver aobserver); attributes attribute type description activewindow nsidomwindow the watcher serves as a global storage facility for the current active (front most non-floating-palette-type) window, storing and returning it on demand.
... void setwindowcreator( in nsiwindowcreator creator ); parameters creator the nsiwindowcreator callback.

Index
1083 nsiwindowcreator interfaces, interfaces:scriptable, xpcom, xpcom api reference, xpcom interface reference create a new window.

nsIXULWindow
contextflags pruint32 contextflags are from nsiwindowcreator2.

XPCOM Interface Reference
me2nsiwebbrowserchrome3nsiwebbrowserchromefocusnsiwebbrowserfindnsiwebbrowserfindinframesnsiwebbrowserpersistnsiwebcontenthandlerregistrarnsiwebnavigationnsiwebnavigationinfonsiwebpagedescriptornsiwebprogressnsiwebprogresslistenernsiwebprogresslistener2nsiwebsocketchannelnsiwebsocketlistenernsiwebappssupportnsiwifiaccesspointnsiwifilistenernsiwifimonitornsiwinaccessnodensiwinapphelpernsiwintaskbarnsiwindowcreatornsiwindowmediatornsiwindowwatchernsiwindowsregkeynsiwindowsshellservicensiworkernsiworkerfactorynsiworkerglobalscopensiworkermessageeventnsiworkermessageportnsiworkerscopensiwritablepropertybagnsiwritablepropertybag2nsixformsmodelelementnsixformsnsinstanceelementnsixformsnsmodelelementnsixmlhttprequestnsixmlhttprequesteventtargetnsixmlhttprequestuploadnsixpcexceptionnsixpcscriptablensixpconnectnsi...

XPCOM Interface Reference by grouping
nsicache nsicachedeviceinfo nsicacheentrydescriptor nsicacheentryinfo nsicachelistener nsicachemetadatavisitor nsicacheservice nsicachesession nsicachevisitor nsicachingchannel nsiselectionimageservice chrome nsisearchengine nsisearchsubmission nsiwebbrowserchrome nsiwindowcreator nsiwindowmediator nsiwindowwatcher clipboard nsiclipboard nsiclipboardcommands nsiclipboarddragdrophooklist nsiclipboarddragdrophooks nsiclipboardhelper nsiclipboardowner core action nsitransactionmanager process ...