drawing off when i change the window size

OpenGL OpenGL: Basic Coding
1

i create 2 simple example
1st
glBindBuffer(GL_ARRAY_BUFFER, *vbo_resize);
glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat)33, obj_resize, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);

	glUseProgram(Program); 
	glBindBuffer(GL_ARRAY_BUFFER, *vbo_resize);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(
		0,				  
		3,                
		GL_FLOAT,        
		GL_FALSE,         
		0,                
		0                
	);
	glDrawArrays( GL_TRIANGLES, 0, 3 );
	glDisableVertexAttribArray(0);
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	glUseProgram(0);

This example not work then i begin to change the size of the program window. Why?

2st example

	glBegin(GL_TRIANGLES);
	  glVertex3f(-1.0f,-0.25f,0.0f);
	  glVertex3f(-0.5f,-0.25f,0.0f);
	  glVertex3f(-0.75f,0.25f,0.0f);
	glEnd();

Work! This example located in the same place.

Image

[ATTACH=CONFIG]925[/ATTACH]

[ATTACH=CONFIG]926[/ATTACH]

If resize stopped , glsl work!

[ATTACH=CONFIG]927[/ATTACH]

2

I don’t know if i understood you correctly but i think, your problem is, that the first example looks wrong when you resize your window, am i correct?
Would you please share two screenshots, one before and one after resizing the window?

3

Okey, add image.