I noticed that in yhkwong's latest SVN builds, I have encountered a problem with keys sticking. This problem does not occur in standard DOSBox 0.74, but I have been unable to check the latest clean SVN builds. Here is a description of the problem :

With Epic Pinball and Pinball Fantasies, the flippers will occasionally get "stuck" in the upwards position when hitting both flipper buttons repeatedly. A distinct press is required to get them back down. This only occurs when using the Shift keys. Pinball Fantasies also supports using the Ctrl keys, and the sticking issue does not affect them.