Ticket #4821: some changes in the algorithm while checking their validity, but this did not help much

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@38196 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Ticket #4821: sorry, this should change sign

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@38197 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
changes related to the on-screen-keyboard (web)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@38198 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e