Font – GNU Radio Companion Toolbar (GRC) on HiDPI 16.04

I've tried to know how to increase the size of the toolbar with tiny icons in GNU Radio Companion (GRC, version, installed on Dell XPS 13, Ubuntu 16.04, with hiDPI . I found this page with recommendations:
But I do not have the file in question, $ HOME / .gtkrc-2.0, and when it's created and saved with "gtk-font-name =" Without 14 "", that does not change anything. I tried to move it to other configuration and GTK folders, without success. Someone has an idea how to proceed?
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