What is wrong with my cat?

We have 2 former stray cats living with us, or ruling our household. They both made the move from Texas to New Mexico with us this past September. They have both been checked out by vets, both here and in Texas prior to our move. First, the male, a solid black that we found lost in our back yard when he was no more than a small handful in size. Next, the female, a grey that was also found in our back yard. She was a few months old when we found her and she had obviously been house trained and someones pet though she did not have any collar or tags. From the first day, she had no problem with entering the house and making herself at home.

At Christmas, we purchased a new living room set, all leather sofa and love seat recliners as well as sofa table, coffee table and 2 end tables. The first day in the house, the cats started trying to claw the furniture.  Since they had already done quite a bit of damage to our other furniture, we decided to have them de-clawed. They seemed to recover fine from the process and since we have no intentions of ever letting them out, not having claws should not be an issue. Actually since moving here, they have made no attempt to even get close to an exterior door. 

As an early riser, I often get up about 5:30 and sit in our breakfast room anticipating the day, reading, computering or just sitting. The cats consider this our time and often climb up to "give me sugar" and curl up close. Even to the point of climbing onto my computer and just laying there like I am not giving them enough attention. 

In mid January, I started taking a computer class at our Community College. So now, I have homework to do and use that early morning quiet time to concentrate on lessons. The grey cat, Rat Cat is her name, has taken it personal that I do not allow her to interrupt my studies. Since the first time I prevented her from climbing up onto my laptop and taking all my attention, she has started becoming a paper shredder. She finds either newspaper, magazine or any other bunch of paper, places her front feet strategically and begins ripping small portions of the paper and spitting them out. I must be diligent about what sort of papers are left lying around. 

I am at a loss as to if this new behavior is due to my not allowing her to get on the computer or the fact that she now has no claws. Perhaps it is just a phase and she will cut it out soon. I will not, however, be taking her to a cat psychologist or psychic or psycho or anything, she will just have to be content in what ever means I decide will be used to retrain her from this bad habit.