I think you should see different number of tabs/windows open for different problems.
There are things in you list that need communication with someone (web and apps - I'd wager they are underspecified). I think you do not need communication working on retro assembly.
I am working on IDE supporting two dirty old languages, VHDL and Verilog. I need three things opened: Visual Studio, PDF of standard under question and orthodox file manager [1] in the tests directory. Having internalized a great deal of VHDL, I do not need it's PDF opened too often. So, there are two things for me to work with: run tests in VS, occasionally look at problematic source code with OFM.
I also need a great deal of silence around me, otherwise I cannot concentrate deep enough to make good decisions and implementation of dirty old languages badly needs extremely good decisions.
