Ligature and Mark position

Hello,
I Would like to talk about some issue occur with Arabic ligature (lamalef-arab) there is more than 8 type, i will take one of them as example: this compose of (“lam-arab.init” and “alef-arab.fina” to compose “lamalef-arab.isol”). every thing is O.K when I position marks with open type feature window, BUT when it comes to test and put the marks it will decompose to its components (lam-arab.init and alef-arab.fina), the normal situation must be like figure 2 (Arial)
fig2.png
.

why this is occurred if the procedure is correct as you will see in the figure1?. is there any tricks designers used?? or there is some thing with open type feature?.
fig1.png
fig3.png
fig4.png
fig5.png
Gasq.otf (84.2 KB)
Gasq.ttf (84.2 KB)

The marks must not be processed to form the ligature:
donotprocessmarks.png

Thank you Mr. Erwin, it is work now :slight_smile: