#3392 Fix crash when selecting Points tab on desktop

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34257 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
NPE fix

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34258 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
DockPanel fix (relevant in devmode only)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34259 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e