This operation will permanently erase all tasks marked as completed. If you continue, you will not be able to recover these tasks. Really erase these tasks?
Bydd y weithred hon yn dileu'n barhaol bob tasg sydd wedi'i marcio wedi'i chwblhau. Os wnewch chi barhau, fedrwch chi ddim adfer y tasgau yma. Dileu'r tasgau yma go iawn?