Comment 3 for bug 1346650

ubuntu-ui-toolkit-examples is uninstallable in that environment indeed: It depends on qtdeclarative5-ubuntu-ui-toolkit-plugin (= 0.1.49+14.10.20140715-0ubuntu1), i. e. a versioned dependency. This won't be satisfied by the "Provides: qtdeclarative5-ubuntu-ui-toolkit-plugin" of qtdeclarative5-ubuntu-ui-toolkit-plugin-gles, but this is installed by default.

So ubuntu-ui-toolkit-examples either needs to drop the strict versioned dependency (so that the Provides: gets effective), or grow an alternative dependency to qtdeclarative5-ubuntu-ui-toolkit-plugin-gles.