fix drop on source text


git-svn-id: http://svn.code.sf.net/p/texstudio/code@4159 92cce386-e96d-4106-809f-596c673a3fd8
activate inputMethod on all platforms (patch by Yuuto Tokunaga)


git-svn-id: http://svn.code.sf.net/p/texstudio/code@4160 92cce386-e96d-4106-809f-596c673a3fd8