Same issue with Safari and spinning beach ball. Even after unchecking Safari in iCloud. This is my console report.
3/4/16 10:51:01.072 AM WindowServer[200]: _CGXRemoveWindowFromWindowMovementGroup: window 0x343 is not attached to window 0x36a
3/4/16 10:51:05.526 AM com.apple.xpc.launchd[1]: (com.apple.WebKit.WebContent.0324319F-01A4-4204-BC75-11019F790397[1073]) Service exited with abnormal code: 1
3/4/16 10:51:05.888 AM WindowServer[200]: _CGXRemoveWindowFromWindowMovementGroup: window 0x343 is not attached to window 0x36a
3/4/16 10:51:06.088 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_ValidateRFC4281CodecId: Unrecognized codec 1.(null). Failed codec specific check.
3/4/16 10:51:06.088 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_LookupCodecSupport: Unrecognized codec 1
3/4/16 10:51:06.090 AM com.apple.WebKit.WebContent[1134]: [10:51:06.089] mv_LowLevelCheckIfVideoPlayableUsingDecoder signalled err=-12956 (kFigMediaValidatorError_VideoCodecNotSupported) (video codec 1) at line 1921
3/4/16 10:51:06.153 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_TestCodecSupportUsingDecoders: Unrecognized codec 1
3/4/16 10:51:06.153 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_ValidateRFC4281CodecId: Unrecognized codec 1.(null). Failed codec specific check.
3/4/16 10:51:06.153 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_LookupCodecSupport: Unrecognized codec 1
3/4/16 10:51:06.153 AM com.apple.WebKit.WebContent[1134]: [10:51:06.153] mv_LowLevelCheckIfVideoPlayableUsingDecoder signalled err=-12956 (kFigMediaValidatorError_VideoCodecNotSupported) (video codec 1) at line 1921
3/4/16 10:51:06.153 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_TestCodecSupportUsingDecoders: Unrecognized codec 1
3/4/16 10:51:07.838 AM WindowServer[200]: _CGXRemoveWindowFromWindowMovementGroup: window 0x343 is not attached to window 0x36a
3/4/16 10:51:10.001 AM com.apple.xpc.launchd[1]: (com.protech.NoSleep[1139]) Service exited with abnormal code: 1
3/4/16 10:51:10.001 AM com.apple.xpc.launchd[1]: (com.protech.NoSleep) Service only ran for 0 seconds. Pushing respawn out by 10 seconds.
3/4/16 10:51:10.971 AM WindowServer[200]: _CGXRemoveWindowFromWindowMovementGroup: window 0x343 is not attached to window 0x36a
3/4/16 10:51:11.097 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_ValidateRFC4281CodecId: Unrecognized codec 1.(null). Failed codec specific check.
3/4/16 10:51:11.097 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_LookupCodecSupport: Unrecognized codec 1
3/4/16 10:51:11.097 AM com.apple.WebKit.WebContent[1134]: [10:51:11.097] mv_LowLevelCheckIfVideoPlayableUsingDecoder signalled err=-12956 (kFigMediaValidatorError_VideoCodecNotSupported) (video codec 1) at line 1921
3/4/16 10:51:11.098 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_TestCodecSupportUsingDecoders: Unrecognized codec 1
3/4/16 10:51:11.098 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_ValidateRFC4281CodecId: Unrecognized codec 1.(null). Failed codec specific check.
3/4/16 10:51:11.098 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_LookupCodecSupport: Unrecognized codec 1
3/4/16 10:51:11.098 AM com.apple.WebKit.WebContent[1134]: [10:51:11.098] mv_LowLevelCheckIfVideoPlayableUsingDecoder signalled err=-12956 (kFigMediaValidatorError_VideoCodecNotSupported) (video codec 1) at line 1921
3/4/16 10:51:11.098 AM com.apple.WebKit.WebContent[1134]: <<<< MediaValidator >>>> mv_TestCodecSupportUsingDecoders: Unrecognized codec 1
3/4/16 10:51:11.804 AM WindowServer[200]: _CGXRemoveWindowFromWindowMovementGroup: window 0x343 is not attached to window 0x36a
3/4/16 10:51:14.737 AM Sidekick[422]: Grandma's Florida scores = {
ALCoreLocationSensor = 0;
}
3/4/16 10:51:14.737 AM Sidekick[422]: Work scores = {
ALCoreLocationSensor = 20;
}
3/4/16 10:51:14.737 AM Sidekick[422]: Home scores = {
ALCoreLocationSensor = 0;
}
3/4/16 10:51:14.737 AM Sidekick[422]: match found, but it's the same as previous match (Work). Ignoring.