I understand well enough now to describe a test, at least.
QSYHNW5ZI242LZFB37ZRXF5YSS4G77IYS25LJ3ZASTVJ2HCOIW5AC MVYYZTAEUWI3M77MSFWYRFFH2SBFWXQGTNP6I44C5SC3BDUBQXVQC FPTS6JMIURRJGEJFPRHOG4HIAASNFN4TOVVOPASCYXRY2V5MZM4QC L32R5DALHPK75E2V7C5QGKR4AH6FVOLGTLMVKVQ36VA5ZKCID2JAC OTIBCAUJ3KDQJLVDN3A536DLZGNRYMGJLORZVR3WLCGXGO6UGO6AC L2R5WULWN44SCNUPP7R7I2AQCWQR6D3E2YZA35RBXZAR2LGC6LQQC BJ5X5O4ACBBJ56LRBBSTCW6IBQP4HAEOOOPNH3SKTA4F66YTOIDAC This doesn't work perfectly at the moment. However, text shouldn't appearsuddenly more than one line's height above the bottom.* Start some way down the surface. Click outside a pane and slowly drag thesurface down. Text should appear smoothly from off screen without anyartifacts around pane boundaries.