Table cell selection flashes when mouse clicks, causes issues for selection dragging, inconsistencies

Could instead use click vs. double click to either select the entire cell, or a specific area similar to spreadsheet programs. Should try to be as consistent as possible with the keyboard shortcuts (e.g. select all when entering cell). Not sure how possible or easy this is with contentEditable tags.

No file or test is named. Reproduce the mouse-click flash and selection-dragging inconsistency in the table, then inspect the contentEditable cell behavior and compare single- and double-click selection with the keyboard shortcuts. Done means cell or area selection is consistent without disrupting dragging.

Written by the indexing model from the issue text.