applications keep freezing while using two screens

I have a MacBook Pro one OS X 10.10.4 and use two screens to work. Lately, applications keep freezing when I switch between screens and I have to constantly force quit them. This using occurs with Mail, Pages and Safari. Here's the data when it occurred today with Mail:

2015-10-03 11:17:46.863 AM WindowServer[165]: Warning: Program "Safari" posted a mouse-down, blocking hardware events, but did no further mouse activity

2015-10-03 11:18:30.951 AM CoreServicesUIAgent[7568]: unexpected message <OS_xpc_error: <error: 0x7fff7ea35c60> { count = 1, contents =

"XPCErrorDescription" => <string: 0x7fff7ea35f70> { length = 18, contents = "Connection invalid" }

}>

2015-10-03 11:18:30.985 AM com.apple.xpc.launchd[1]: (com.apple.WebKit.WebContent.48490B30-BD84-47B3-81BE-9D0A6DF1B26B[7947]) Service exited with abnormal code: 1

2015-10-03 11:18:31.049 AM sharingd[268]: 11:18:31.048 : SDConnectionManager:: XPC connection invalidated

2015-10-03 11:18:31.520 AM com.apple.xpc.launchd[1]: (com.apple.mail.29000[7943]) Service exited due to signal: Terminated: 15

2015-10-03 11:18:55.308 AM com.apple.WebKit.WebContent[8093]: BUG in libdispatch: 14F27 - 2943 - 0x4

2015-10-03 11:18:55.311 AM com.apple.xpc.launchd[1]: (com.apple.WebKit.WebContent.FCBFD1B7-F2DC-4349-A0D0-6A7C6196FC68[8093]) Service exited with abnormal code: 1

2015-10-03 11:19:17.495 AM com.apple.xpc.launchd[1]: (com.apple.imfoundation.IMRemoteURLConnectionAgent) The _DirtyJetsamMemoryLimit key is not available on this platform.

2015-10-03 11:19:38.629 AM WindowServer[165]: Warning: Program "Safari" posted a mouse-down, blocking hardware events, but did no further mouse activity

2015-10-03 11:19:57.995 AM com.apple.xpc.launchd[1]: (com.apple.imfoundation.IMRemoteURLConnectionAgent) The _DirtyJetsamMemoryLimit key is not available on this platform.

2015-10-03 11:21:40.801 AM Safari[249]: Failed to save record: <CKError 0x7ff708ad13c0: "Internal Error" (1/5001); "Fetched zone had no protection data: <CKRecordZone: 0x7f83f3ddfcc0; zoneID=History:__defaultOwner__, capabilities=(Atomic,Sync)>">

2015-10-03 11:24:09.189 AM com.apple.xpc.launchd[1]: (com.apple.quicklook[8097]) Endpoint has been activated through legacy launch(3) APIs. Please switch to XPC or bootstrap_check_in(): com.apple.quicklook

2015-10-03 11:24:47.317 AM Console[8098]: Failed to connect (_consoleX) outlet from (NSApplication) to (ConsoleX): missing setter or instance variable

2015-10-03 11:24:51.780 AM Console[8098]: The function ‘CGContextErase’ is obsolete and will be removed in an upcoming update. Unfortunately, this application, or a library it uses, is using this obsolete function, and is thereby contributing to an overall degradation of system performance.