[gnome] problem with common keyboard shortcut keys in text fields/editors

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http://ubuntuforums.org – I am running a ubuntu 12.04 64 bit system with cinnamon 1.6. Some keyboard shortcuts such as ctrl+a for select all and ctrl+w for close tab do not seem to work in text editors and text fields. On pressing ctrl+a the cursor just moves to the 1st character of the text field. however ctrl+a does work elsewhere like in nautilus, firefox (non text fields). I need this badly since I do a lot of programming in gedit. Any idea what might be the problem and how it might be solved? Note: I later discovered that Alt+A works for text fields in firefox, but nowhere else. (Hardware)