c# - Why are some of my TabIndex values not being respected? -

i've got form several controls on them (textbox, checkbox, combobox, numericupdown, datetimepicker, , button).

i have assigned them tabindex values, left-to-right, top-to-bottom (1..25).

the controls organized panels. first control in top panel has focus first; tabbing there goes through first panel fine, jumps on second , third panels fourth panel (skipping tabindex 11..15 on panels 2 , 3 , going tabindex 16 on panel 4).

all of controls have tabstop set true; of panels have tabstop set false.

why controls on panels 2 , 3 being bypassed?

update

tntinmn inspired me check out; had never noticed option before. here form looks view:

this seems macabre, wacky even, had give panels tabindex values in incrementing values work. say, after gave first panel tabindex of 0, second panel 1, etc., worked - though set tabstop = false.

seems bizarre me unstopped location considered @ in tabbing scheme of things.