TYPO3 Core

I am using TYPO3 7 (latest master).
1) set up a custom workspace
2) every time I switch workspaces using the dropdown I get 3 warnings on the right

Connection Problem
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There is an error on the chrome console:

POST http://typo37.basic.it/typo3/ajax.php?ajaxID=ExtDirect::route&namespace=TYPO3.Components.PageTree 500 (Internal Server Error)asyncRequest @ ext-base-debug.js:2429Ext.lib.Ajax.pub.request @ ext-base-debug.js:2484Ext.extend.request @ ext-all-debug.js:4636Ext.direct.RemotingProvider.Ext.extend.doSend @ ext-all-debug.js:27367Ext.direct.RemotingProvider.Ext.extend.combineAndSend @ ext-all-debug.js:27373call @ ext-all-debug.js:1566
ext-base-debug.js:2429 POST http://typo37.basic.it/typo3/ajax.php?ajaxID=ExtDirect::route&namespace=TYPO3.Components.PageTree 500 (Internal Server Error)asyncRequest @ ext-base-debug.js:2429Ext.lib.Ajax.pub.request @ ext-base-debug.js:2484Ext.extend.request @ ext-all-debug.js:4636Ext.direct.RemotingProvider.Ext.extend.doSend @ ext-all-debug.js:27367Ext.direct.RemotingProvider.Ext.extend.combineAndSend @ ext-all-debug.js:27373call @ ext-all-debug.js:1566
Ext.ux.state.TreePanel.js?1429865803:90 Uncaught TypeError: Cannot read property 'lastSelectedNode' of undefined