User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0 Build ID: 20150723165742 Steps to reproduce: When I go fullscreen I get a black box appear that appears to hover over the window(no action in the window affects it). It is suggested that this is the shadow of a tooltip. Its position changes based around the size of the window before going fullscreen( by hitting F11 or by using flash/html5/silverlight fullscreen). The bug appears with all plugins addons and extensions disabled. Images of bug: http://gyazo.com/65337388c6b0d1b2ea91fd4dda2c29b4 http://gyazo.com/01cbd6c9807dd7114c46cf1906a75cee http://gyazo.com/bd33e9c463a6cf0db4ca4130485f418d http://gyazo.com/1ee709a8452b32ced87e98b92f2ce2a9 Actual results: raw data: { "application": { "name": "Firefox", "version": "40.0", "buildID": "20150723165742", "userAgent": "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0", "updateChannel": "beta", "supportURL": "https://support.mozilla.org/1/firefox/40.0/WINNT/en-US/", "numTotalWindows": 2, "numRemoteWindows": 0, "remoteAutoStart": false }, "modifiedPreferences": { "accessibility.typeaheadfind.flashBar": 0, "browser.cache.disk.smart_size.first_run": false, "browser.cache.disk.smart_size.use_old_max": false, "browser.cache.disk.capacity": 358400, "browser.cache.disk.filesystem_reported": 1, "browser.cache.frecency_experiment": 4, "browser.download.importedFromSqlite": true, "browser.download.manager.alertOnEXEOpen": true, "browser.places.smartBookmarksVersion": 7, "browser.search.useDBForOrder": true, "browser.sessionstore.upgradeBackup.latestBuildID": "20150723165742", "browser.startup.homepage_override.mstone": "40.0", "browser.startup.homepage": "about:newtab", "browser.startup.homepage_override.buildID": "20150723165742", "dom.apps.reset-permissions": true, "dom.mozApps.used": true, "extensions.lastAppVersion": "40.0", "font.internaluseonly.changed": false, "gfx.direct3d.last_used_feature_level_idx": 0, "media.gmp-eme-adobe.trial-create": 1, "media.gmp-eme-adobe.lastUpdate": 1437750060, "media.gmp-gmpopenh264.lastUpdate": 1431039803, "media.gmp-gmpopenh264.version": "1.4", "media.gmp-eme-adobe.version": "12", "media.gmp-gmpopenh264.enabled": true, "media.gmp-manager.lastCheck": 1437998820, "media.gmp-manager.buildID": "20150723165742", "network.cookie.prefsMigrated": true, "network.predictor.cleaned-up": true, "places.history.expiration.transient_current_max_pages": 104858, "places.database.lastMaintenance": 1437948522, "plugin.state.npvlc": 2, "plugin.state.npdivx": 1, "plugin.importedState": true, "plugin.state.npctrl": 2, "plugin.state.npgoogletalk": 2, "plugin.state.npgtpo3dautoplugin": 2, "plugin.state.nppdf": 2, "plugin.state.npnv3dvstreaming": 2, "plugin.state.npnv3dv": 2, "plugin.state.npwlpg": 2, "plugin.disable_full_page_plugin_for_types": "application/pdf", "plugin.state.npo1d": 2, "plugin.state.npbattlelog": 1, "plugin.state.npdeployjava": 1, "plugin.state.npgoogleupdate": 2, "plugin.state.npqtplugin": 1, "plugin.state.npwacomtabletplugin": 2, "plugin.state.npovshelper": 1, "print.printer_HP_Officejet_6500_E709n_Series.print_command": "", "print.printer_HP_Officejet_6500_E709n_Series.print_page_delay": 50, "print.printer_HP_Officejet_6500_E709n_Series.print_footerright": "&D", "print.printer_HP_Officejet_6500_E709n_Series.print_edge_right": 0, "print.printer_HP_Officejet_6500_E709n_Series.print_footercenter": "", "print.printer_HP_Officejet_6500_E709n_Series.print_unwriteable_margin_right": 0, "print.printer_HP_Officejet_6500_E709n_Series.print_headerleft": "&T", "print.printer_HP_Officejet_6500_E709n_Series.print_unwriteable_margin_bottom": 0, "print.printer_HP_Officejet_6500_E709n_Series.print_reversed": false, "print.printer_HP_Officejet_6500_E709n_Series.print_bgimages": false, "print.printer_HP_Officejet_6500_E709n_Series.print_in_color": true, "print.printer_HP_Officejet_6500_E709n_Series.print_to_file": false, "print.printer_HP_Officejet_6500_E709n_Series.print_paper_width": " 8.50", "print.printer_HP_Officejet_6500_E709n_Series.print_margin_bottom": "0.5", "print.printer_HP_Officejet_6500_E709n_Series.print_unwriteable_margin_top": 0, "print.printer_HP_Officejet_6500_E709n_Series.print_bgcolor": false, "print.printer_HP_Officejet_6500_E709n_Series.print_plex_name": "", "print.printer_HP_Officejet_6500_E709n_Series.print_scaling": " 1.00", "print.printer_HP_Officejet_6500_E709n_Series.print_headercenter": "", "print.printer_HP_Officejet_6500_E709n_Series.print_shrink_to_fit": true, "print.printer_HP_Officejet_6500_E709n_Series.print_colorspace": "", "print.printer_HP_Officejet_6500_E709n_Series.print_unwriteable_margin_left": 0, "print.printer_HP_Officejet_6500_E709n_Series.print_margin_left": "0.5", "print.printer_HP_Officejet_6500_E709n_Series.print_duplex": 1515870810, "print.printer_HP_Officejet_6500_E709n_Series.print_headerright": "&U", "print.printer_HP_Officejet_6500_E709n_Series.print_margin_top": "0.5", "print.printer_HP_Officejet_6500_E709n_Series.print_orientation": 0, "print.printer_HP_Officejet_6500_E709n_Series.print_edge_top": 0, "print.printer_HP_Officejet_6500_E709n_Series.print_paper_size_unit": 0, "print.printer_HP_Officejet_6500_E709n_Series.print_evenpages": true, "print.printer_HP_Officejet_6500_E709n_Series.print_edge_bottom": 0, "print.printer_HP_Officejet_6500_E709n_Series.print_paper_data": 1, "print.printer_HP_Officejet_6500_E709n_Series.print_margin_right": "0.5", "print.printer_HP_Officejet_6500_E709n_Series.print_edge_left": 0, "print.printer_HP_Officejet_6500_E709n_Series.print_paper_name": "", "print.printer_HP_Officejet_6500_E709n_Series.print_downloadfonts": false, "print.printer_HP_Officejet_6500_E709n_Series.print_footerleft": "&PT", "print.printer_HP_Officejet_6500_E709n_Series.print_paper_height": " 11.00", "print.printer_HP_Officejet_6500_E709n_Series.print_resolution_name": "", "print.printer_HP_Officejet_6500_E709n_Series.print_resolution": 1515870810, "print.printer_HP_Officejet_6500_E709n_Series.print_paper_size_type": 0, "print.printer_HP_Officejet_6500_E709n_Series.print_oddpages": true, "privacy.sanitize.timeSpan": 0, "privacy.cpd.downloads": false, "privacy.cpd.cookies": false, "privacy.sanitize.migrateFx3Prefs": true, "privacy.cpd.formdata": false, "privacy.cpd.history": false, "privacy.cpd.sessions": false, "storage.vacuum.last.places.sqlite": 1437007514, "storage.vacuum.last.index": 1 }, "lockedPreferences": {}, "graphics": { "numTotalWindows": 2, "numAcceleratedWindows": 2, "windowLayerManagerType": "Direct3D 11", "windowLayerManagerRemote": true, "supportsHardwareH264": true, "adapterDescription": "NVIDIA GeForce GTX 770", "adapterVendorID": "0x10de", "adapterDeviceID": "0x1184", "adapterSubsysID": "103310de", "adapterRAM": "2048", "adapterDrivers": "nvd3dumx,nvwgf2umx,nvwgf2umx nvd3dum,nvwgf2um,nvwgf2um", "driverVersion": "9.18.13.4752", "driverDate": "2-5-2015", "adapterDescription2": "", "adapterVendorID2": "", "adapterDeviceID2": "", "adapterSubsysID2": "", "adapterRAM2": "", "adapterDrivers2": "", "driverVersion2": "", "driverDate2": "", "isGPU2Active": false, "direct2DEnabled": true, "directWriteEnabled": true, "directWriteVersion": "6.2.9200.17292", "webglRenderer": "Google Inc. -- ANGLE (NVIDIA GeForce GTX 770 Direct3D11 vs_5_0 ps_5_0)", "info": { "AzureCanvasBackend": "direct2d 1.1", "AzureSkiaAccelerated": 0, "AzureFallbackCanvasBackend": "cairo", "AzureContentBackend": "direct2d 1.1" } }, "javaScript": { "incrementalGCEnabled": true }, "accessibility": { "isActive": false, "forceDisabled": 0 }, "libraryVersions": { "NSPR": { "minVersion": "4.10.8", "version": "4.10.8" }, "NSS": { "minVersion": "3.19.2 Basic ECC", "version": "3.19.2 Basic ECC" }, "NSSUTIL": { "minVersion": "3.19.2", "version": "3.19.2" }, "NSSSSL": { "minVersion": "3.19.2 Basic ECC", "version": "3.19.2 Basic ECC" }, "NSSSMIME": { "minVersion": "3.19.2 Basic ECC", "version": "3.19.2 Basic ECC" } }, "userJS": { "exists": false }, "crashes": { "submitted": [], "pending": 0 }, "extensions": [ { "name": "Adblock Plus", "version": "2.6.9.1-signed", "isActive": true, "id": "{d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}" }, { "name": "Reddit Enhancement Suite", "version": "4.5.4.1-signed", "isActive": true, "id": "jid1-xUfzOsOFlzSOXg@jetpack" }, { "name": "XKit", "version": "7.4.5", "isActive": true, "id": "xkit@studioxenix.com" }, { "name": "DivX Plus Web Player HTML5 <video>", "version": "2.1.2.172", "isActive": false, "id": "{23fcfd51-4958-4f00-80a3-ae97e717ed8b}" }, { "name": "Freemake Video Downloader Plugin", "version": "1.0.0", "isActive": false, "id": "fmdownloader@gmail.com" }, { "name": "Freemake Youtube Download Button", "version": "1.0.0", "isActive": false, "id": "ytfmdownloader@gmail.com" }, { "name": "Norton Toolbar", "version": "2014.7.12.28", "isActive": false, "id": "{2D3F3651-74B9-4795-BDEC-6DA2F431CB62}" } ], "experiments": [] } Expected results: Running firefox 40.0b7

not caused by hardware acceleration or about:config?filter=layers.offmainthreadcomposition.enabled tested in #firefox

bug first appears on 7-17-15 nightly

Duplication of Bug 1186886