Hello!.I am using tkinter,you are correct.I tried your code but did not make it work. This a snippet.Enough to fix the issue,i guess.
def start(self):
self.w=Label(self.root,text="Πρόσθεση πινάκων παραδείγματα",font="Arial 12")
self.w.grid(row=1,column=1)
self.w1=Label(self.root,text="Διάλεξε τις διαστάσεις του πρώτου πίνακα",font="Arial 12")
self.w1.grid(row=2,column=1)
self.s1=Label(self.root,text="X:",font="Arial 10")
self.entry1=Entry(self.root,font="Arial 12",bg="#d9d9d9",width=5)
self.entry1.grid(row=3,column=1)
self.s2=Label(self.root,text="Y:",font="Arial 10")
self.s2.grid(row=4,column=1)
self.entry2=Entry(self.root,font="Arial 12",bg="#d9d9d9",width=5)
self.entry2.grid(row=4,column=1)
self.w2=Label(self.root,text="Διάλεξε τις διαστάσεις του δεύτερου πίνακα",font="Arial 12")
self.w2.grid(row=5,column=1)
self.s3=Label(self.root,text="X:",font="Arial 10")
self.s3.grid(row=6,column=1)
self.entry3=Entry(self.root,font="Arial 12",bg="#d9d9d9",width=5)
self.entry3.grid(row=6,column=1)
self.s4=Label(self.root,text="Y:",font="Arial 10")
self.s4.grid(row=7,column=1)
self.entry4=Entry(self.root,font="Arial 12",bg="#d9d9d9",width=5)
self.entry4.grid(row=7,column=1)
self.w3=Button(self.root,text="Must be gone when clicked",font="Arial 12",bg="#d9d9d9",command=self.multi)
self.w3.grid(row=8,column=1)
the self.multi command is this def
def multi(self):
self.check() #verifies some variables,ignore
self.w3.lower()# tries to minimize the button
def multi(self):
self.check()
self.w3['state']=DISABLED ##lockes the button upon click!
Managed to do it!.I locked it.Its ok and works. Thanks!